Film developers compared

Six developers, one manufacturer, and a fifty-year run of documents that describe them in each other’s terms. That is why this is the matrix the brief enumerates sixteen properties for: Kodak published these formulas as a family, with a keeping table that puts them in one column and a packed-developer list that names what each is for, and the comparison is therefore something the sources support rather than something a reader has to assemble.

!Read the empty columns first

Five of the sixteen — compensating, scanning suitability, push processing for five of the six, and the negatives for hand-coated processes — have almost nothing in them. That is not the matrix failing to do its job. D-23 is described as a compensating developer nearly everywhere it is mentioned, and Kodak’s word for it is soft-working; the course looked for the manufacturer statement and did not find one, so the cell says that instead of repeating what circulates.

⁇Two pages of this course disagree about one number

Building the capacity column found a disagreement inside the reference itself. DK-50’s page says its 48 sheets is the highest deep-tank figure of any developer on the 1949 table; D-19b’s page says its own 72 is the highest figure on the whole developer table. Both cannot be right.

The matrix records the disagreement in both cells rather than settling it, because settling it means re-reading Kodak Limited’s keeping table and neither page can be corrected from the other. What is not in dispute is the shape of the table: DK-50 takes 24 sheets in a dish and 48 in a tank, D-19b takes 36 and 72, and the four remaining developers take 24 and 36 apart from D-25, which takes 20 and 30.

Film developers

Six Kodak negative developers on the sixteen axes brief section 16 names, with the reasoning and the source under every score and an argued blank where the evidence stops.

9 subjects on 16 axes. 89 of the 144 cells carry a score with its reasoning and its source; 55 are not established, of which 21 say why for that subject in particular and 34 are answered by their column's own note. 12 scored cells are marked inferred, meaning the course reasoned them out of something a source states rather than reading them off it.

What is in this matrix, and what is not

Nine film developers, and the reason there are nine rather than six is Part XXVII. The first six are the Kodak formulas this course wrote from primary Kodak documents, which are the six that teach different things: the borax standard, the two-ingredient soft-working bath, the minimum-grain bath and its published exposure penalty, the thiocyanate extra-fine-grain bath, the brisk metaborate working developer, and the high-contrast bath. The last three are the developers Part XXVII's closing assignment asks a student to run against D-76 and against each other, and they are here so that a student's four rows have somewhere to land: Beutler, which gets its sharpness by leaving out the sulfite every fine-grain developer is built on; PMK, which develops to a silver image and a stain at the same time; and the rodinal-type p-aminophenol concentrate as Wall printed it in 1924. The four replenishers in the formulary are not columns here, because a replenisher is not a developer and has no grain, speed or contrast of its own. D-19 is not a column either: it is the earlier printing of the same high-contrast design as D-19b, its own page says the two are not interchangeable at the same time, and the 1928 primer that carries it publishes neither a keeping table nor a capacity. The fourth developer of Part XXVII's assignment, XTOL, is not a column, and its absence is a decision rather than an oversight. This matrix compares published formulas, and XTOL is a bought product whose composition Kodak has never published - which is why it carries a product page in the formulary and not a formula page. Letting it in would put a row here whose composition-facing columns, grain and acutance and cost and complexity, were empty for a different reason from every other blank in the table, and a blank that means two things means nothing. A student who runs the assignment produces four rows and three of them land here; the XTOL row belongs in their own report. For what Kodak does publish, and for the nearest open formula printed beside it, read the XTOL product page in the formulary; for the assignment that sets all four developers against one another, read Part XXVII's developer comparison.

Film developers: every axis against every subject. Each score links to the section that argues it.

Axis	D-76the borax standard	D-23two ingredients	D-25minimum grain	DK-20thiocyanate	DK-50brisk, general	D-19bhigh contrast	Beutlerhigh acutance	PMKstaining	Rodinal typeWall, 1924
Grain	Fine3/5	Fine3/5	Minimum5/5	Extra fine4/5	Moderate2/5*, an inference by this course	Coarse1/5*, an inference by this course	Coarse1/5	—not established	—not established
Sharpness	Moderate2/3	Moderate2/3*, an inference by this course	Low1/3*, an inference by this course	Low1/3*, an inference by this course	High3/3*, an inference by this course	—not established	High3/3	High3/3	High3/3*, an inference by this course
Effect on film speed	No loss claimed2/2	No loss claimed2/2	Published loss1/2	—not established	—not established	—not established	—not established	—not established	—not established
Contrast	Normal2/3	Soft1/3	Soft1/3	Normal2/3	Normal2/3	High3/3	—not established	—not established	—not established
Compensating	—not established	—not established	—not established	—not established	—not established	—not established	—not established	—not established	—not established
Shelf life	Months4/5	Months4/5	Months4/5	Months4/5	Months4/5	Months4/5	—not established	Indefinite5/5	—not established
One-shot or reusable	Either	Either	Either	Replenished	Reusable	Replenished	One-shot	One-shot	—not established
Cost	£1/4*, an inference by this course	£1/4*, an inference by this course	£1/4*, an inference by this course	—not established	—not established	£1/4*, an inference by this course	£1/4*, an inference by this course	—not established	—not established
Complexity	Moderate2/4	Simple1/4	Simple1/4	Moderate2/4	Simple1/4	Moderate2/4	Moderate2/4	Involved3/4	Involved3/4
Safety classification	Level B2/4	Level B2/4	Level B2/4	Level B2/4	Level B2/4	Level B2/4	Level B2/4	Level B2/4	Level B2/4
Waste stream	Developer stream	Developer stream	Developer stream	Developer stream	Developer stream	Developer stream	Developer stream	Developer stream	Developer stream
Suitability for scanning	—not established	—not established	—not established	—not established	—not established	—not established	—not established	—not established	—not established
Materials it is published for	Film and plates	Film and plates	Film and plates	Film and plates	Film and plates	Film, plates and paper	Film and plates	Film and plates	Film, plates and paper
Sheet film	Yes	Yes	Yes	Yes	Yes	Yes	—not established	Yes	Yes, with a condition
Push processing	Yes, with a condition	—not established	—not established	—not established	—not established	—not established	—not established	—not established	—not established
Negatives for hand-coated processes	—not established	—not established	—not established	—not established	—not established	—not established	—not established	—not established	—not established

— not established: the column's own note, or the cell's, says what is missing. * an inference by this course from something a source states, rather than a statement a source makes. Every score in the grid is a link to the paragraph that argues it. 3 of the 16 axes are empty for every subject (Compensating, Suitability for scanning, Negatives for hand-coated processes), and each of them says why in its own section.

Grain

The question Where does the maker place this developer in its own grain vocabulary, and what in the formula puts it there?

Every one of these scores is a maker's word rather than a granularity measurement. Kodak publishes granularity figures for films, not for developers, and the course holds none for these six.

The scale: Grain, ordered

Where the maker's own published vocabulary places the developer, from a bath made for gradient with no regard to grain to one sold on grain alone.

1. 1CoarseGrain is not among the things the formula was designed for, and the maker does not claim otherwise.
2. 2ModerateA working developer with no solvent load worth the name; coarser than the fine-grain baths and by design.
3. 3FineThe maker's phrase is fine grain, and there is enough sulfite in the formula to do solvent work.
4. 4Extra fineThe maker's phrase is extra fine grain, reached by adding a second silver solvent to the sulfite.
5. 5MinimumThe maker's own superlative, and the reason the formula exists; every other property is subordinated to it.

Where a cell is empty The maker publishes no grain claim for the formula and the course has run no comparison of its own. Grain is a property of the developer and the emulsion together, so it cannot be inferred from the ingredient list alone beyond the direction the sulfite load points in.

D-76the borax standard

Fineposition 3 of 5stated by the source

Kodak's own word for the stock solution is fine grain, and the formula says where it comes from: 100 g of sodium sulfite per litre, acting as a silver solvent rather than only as a preservative. The 1928 primer makes the same point from the other direction, noting that substituting carbonate for the borax accentuates graininess. At 1+1 the same sulfite is halved and the grain coarsens, which Kodak publishes as the price of the extra sharpness.

Sources:Kodak Limited, 1949§ Kodak formula D-76 and its metric column; Some Kodak packed developers · Eastman Kodak Company, 1928§ Fine Grain Negative Developer Formula for Motion Pictures D-76; borax and the high sulphite of D-76 as a solvent for silver bromide; the accentuation of graininess when carbonate is substituted

Argued in:D-76, image characteristics

D-23two ingredients

Fineposition 3 of 5stated by the source

The same 100 g of sulfite per litre that does the solvent work in D-76, in a bath that has nothing else in it but 7.5 g of metol. The grain claim is therefore the sulfite's, not the agent's, and the pairing of these two formulas is the clearest evidence in this reference that fine grain in a Kodak developer is bought with sulfite.

Sources:Kodak Limited, 1949§ Kodak formula D-23 and its metric column, with its description

Argued in:D-23, image characteristics

D-25minimum grain

Minimumposition 5 of 5stated by the source

Minimum grain is Kodak's own superlative for this formula and the reason it exists: D-23 with 15 g per litre of sodium bisulfite added, which drops the pH and slows development until the solvent action has longer to work. It is the only developer in this column for which the maker publishes a cost in exposure alongside the claim, which is what makes the claim credible rather than promotional.

Sources:Kodak Limited, 1949§ Kodak formula D-25, with its description, its exposure warning and its development time

Argued in:D-25, image characteristics

DK-20thiocyanate

Extra fineposition 4 of 5stated by the source

Kodak's phrase is extra fine grain, and the mechanism is a second silver solvent rather than more of the first: potassium thiocyanate alongside the sulfite, at a higher pH than D-25 reaches. D-25 and DK-20 are the same manufacturer answering the same question twice by different routes, which is why they sit at different points on this scale rather than at the same one.

Sources:Kodak Limited, 1949§ Kodak formula DK-20, with its dissolving instruction and its development time; Some Kodak packed developers

Argued in:DK-20, image characteristics

DK-50brisk, general

Moderateposition 2 of 5an inference by this course

Kodak makes no grain claim for DK-50 at all, and 30 g of sulfite per litre is not a solvent load: it is a preservative dose, a third of what D-76 and D-23 carry. The score is the course reading the formula against the two developers either side of it rather than a maker's word, and the direction is the one the 1928 primer's own account of sulfite as a solvent requires.

Sources:Kodak Limited, 1949§ Kodak formula DK-50, with its dissolving instruction, its note on varying the Kodalk and its development time · Eastman Kodak Company, 1928§ The high sulphite of D-76 as a solvent for silver bromide

Argued in:DK-50, image characteristics

D-19bhigh contrast

Coarseposition 1 of 5an inference by this course

A high-contrast bath carrying 72 g of anhydrous sulfite, 8.8 g of hydroquinone and 48 g of anhydrous carbonate a litre: the alkali, not the solvent, is what this formula is built around. Kodak publishes no grain claim, and the course scores it coarse on the same reading of sulfite against alkali that places DK-50, while recording that the work D-19b was made for - line, copy, X-ray and scientific record - is work in which grain is not a criterion.

Sources:Kodak Limited, 1949§ Kodak formula D-19b and its metric column · Eastman Kodak Company, 1928§ The accentuation of graininess when carbonate is substituted for borax

Argued in:D-19b, image characteristics

Beutlerhigh acutance

Coarseposition 1 of 5stated by the source

The British Journal annual files the formula under acutance developers "for maximum sharpness at some loss of fine grain", which names the cost in the same line as the benefit, and Haist gives the design principle it follows from: Beutler found that any developer containing a high concentration of a silver halide solvent gives unsharp negatives. Taking the solvent out takes the grain mechanism with it. The working bath carries 4.17 g of sulfite a litre against D-76's 100, and the technique's own answer to grain is to start with a slower film rather than a different developer.

Sources:Geoffrey Crawley (editor), 1972§ Acutance formulae, for maximum sharpness at some loss of fine grain - The Beutler Developer · Grant Haist, 1979§ High-definition developers - Beutler's finding on silver halide solvents and unsharp negatives

Argued in:Beutler, image characteristics

PMKstaining

Not established

One maker claims fine grain and the bath has nothing in it to make grain fine. BERGGER states that the grain is reduced, and reduced further at 27 degrees C; the working solution contains no silver solvent at all - no sulfite worth the name, no thiocyanate, no carbonate at fine-grain concentrations - so there is no dissolution mechanism for the claim to rest on. BERGGER's own explanation is that the stain fills the space between the grains, which is an optical effect rather than a physical one, and the alternative is that the tanning does it. No measurement is published for either reading and the course does not choose between them.

Sources:BERGGER, 2020§ PMK properties - the grain claim and the yellow-green tint filling the space between grains

Argued in:PMK, image characteristics

Rodinal typeWall, 1924

Not established

The one axis in this row where a maker and the arithmetic disagree outright. Foma calls its manufactured equivalent a fine-grain para-aminophenol developer, which is a maker's description of its own product and also marketing copy. Against that, a rodinal-type concentrate at 1:40 carries about 0.033 mol/L of sulphite where D-76 carries 0.79, and at the 1+50 the manufacturer publishes it is thirty times below: there is not enough sulphite in a working bath of this class to do solvent work at all. What would settle it is a measured grain comparison on one film against D-76, and nothing in the corpus supplies one.

Sources:FOMA BOHEMIA spol. s r.o., 2023§ FOMADON R 09 - the general description as a fine-grain para-aminophenol developer · E. J. Wall, F.C.S., F.R.P.S., 1924§ Developers, pages 108 and 109 - the paramidophenol one-solution formula and its dilutions

Argued in:Rodinal type, image characteristics

Sharpness

The question What does the maker publish, or the sulfite load imply, about edge detail in this developer?

Three of these six scores are marked inferred. Kodak states a sharpness trade only for D-76 at 1+1; the rest of the column reasons from how much silver solvent is in the bath, which is an argument the formulary pages make and not a measurement.

The scale: Sharpness, ordered

How the formula treats edge detail, which in a silver developer is mostly a question of how much silver its solvents move about before development finishes.

1. 1LowA solvent-heavy bath. Dissolved silver migrates, and an edge is the first thing that suffers.
2. 2ModerateEnough solvent to affect grain, not so much that the maker offers a sharper way of using the same bath without comment.
3. 3HighThe maker offers this dilution or this formula specifically for sharpness, and states what it costs.

Where a cell is empty The document that carries the formula says nothing about sharpness, and the formula was written for a job in which sharpness was not the criterion. The course will not turn silence into a low score: a developer nobody characterised for acutance is not thereby a soft one.

D-76the borax standard

Moderateposition 2 of 3stated by the source

Kodak publishes the trade rather than a rating: dilute the stock 1+1 for greater sharpness, at a slight cost in graininess. That makes stock-strength D-76 the moderate case by the maker's own account, since the maker is offering a sharper way of using the same bath and saying what it costs. It is the only sharpness statement in this whole column that is not the course reasoning from sulfite.

Sources:Kodak Alaris Inc., 2017§ The opening description; development-time tables at full strength and 1:1

Argued in:D-76, behaviour at 1+1

D-23two ingredients

Moderateposition 2 of 3an inference by this course

Kodak says nothing about sharpness in this formula. The course places it with D-76 at stock strength because it carries the same 100 g of sulfite per litre and nothing else that moves silver, and dissolved silver migrating before development finishes is what blunts an edge. This is an argument from the ingredient list and is marked as one.

Sources:Eastman Kodak Company, 1928§ Chapter II, the preservative and the behaviour of sodium sulphite as a solvent for silver bromide

Argued in:D-23, image characteristics

D-25minimum grain

Lowposition 1 of 3an inference by this course

The most solvent-heavy bath in this column: D-23's sulfite plus bisulfite, worked at a lower pH so that the solvent action has longer to act before development completes. Everything that buys the minimum-grain claim works against an edge, and the course scores it accordingly while recording that Kodak publishes no sharpness figure for it.

Sources:Kodak Limited, 1949§ Kodak formula D-25, with its description and its exposure warning

Argued in:D-25, image characteristics

DK-20thiocyanate

Lowposition 1 of 3an inference by this course

Two silver solvents in one bath - the sulfite and the thiocyanate - is the opposite of an acutance developer, and the formulary page says so in exactly those terms. Kodak publishes no sharpness statement, so the score is the course's reading of what the second solvent is there to do.

Sources:Kodak Limited, 1949§ Kodak formula DK-20, with its dissolving instruction

Argued in:DK-20, when another formula is preferable

DK-50brisk, general

Highposition 3 of 3an inference by this course

The least solvent-loaded bath here that Kodak still publishes for ordinary pictorial negatives: 30 g of sulfite a litre against D-76's 100. The formulary page argues that its sharpness advantage and its coarser grain are the same fact seen twice. Kodak states neither, so this is the course's inference and the strongest one in the column, since it rests on a threefold difference in the ingredient that does the work.

Sources:Kodak Limited, 1949§ Kodak formula DK-50 and its metric column

Argued in:DK-50, image characteristics

D-19bhigh contrast

Not established

Kodak publishes nothing about sharpness for D-19b and the formulary page declines to score it, on the ground that acutance was not a design consideration for the work this bath was made for. That is a statement about intent and not about performance, and the course will not convert one into the other.

Sources:Kodak Limited, 1949§ Kodak formula D-19b and its metric column

Argued in:D-19b, image characteristics

Beutlerhigh acutance

Highposition 3 of 3stated by the source

The only formula in this matrix whose sources introduce it as an acutance developer before they say anything else: the Encyclopedia of Photography names it as one of the best known high-acutance developers, and the annual's section heading states the trade outright. Beutler's own claim, which Windisch reports at one remove and this course passes on as a claim, is up to 141 lines per millimetre on films and targets nobody specifies. What is not a claim is the arithmetic: 0.83 g of metol and 4.17 g of sulfite in a litre leave almost nothing to move silver about before development finishes.

Sources:Willard D. Morgan (editor in chief), 1963§ Developers, the acutance paragraph naming the Beutler formula · Hans Windisch, 1956§ A special developer for low-speed films, a Willi Beutler formula - Beutler's claim of up to 141 lines per millimetre

Argued in:Beutler, image characteristics

PMKstaining

Highposition 3 of 3stated by the source

Both makers put sharpness first and neither publishes a measurement of it: BERGGER's phrase is that the definition is more pronounced and the outlines very sharp, and Photographers' Formulary lists sharpness first and edge effects fourth among the criteria the formula was constituted to satisfy. What the course adds is the reason the claim is at least consistent - the working bath holds under a gram of pyrogallol, a fifth of a gram of preservative and no silver solvent whatever, which is the condition adjacency effects need.

Sources:BERGGER, 2020§ PMK properties - the definition and the sharpness of the outlines · Photographers' Formulary Inc.§ The opening paragraph on what the formula is constituted to achieve - sharpness, maximum image stain, minimum general stain, edge effects

Argued in:PMK, image characteristics

Rodinal typeWall, 1924

Highposition 3 of 3an inference by this course

No maker offers this developer for sharpness and neither Wall nor Foma publishes an acutance measurement, so the placement is the course's argument and is marked as one. It rests on two properties the sources do establish: a working bath at 1:40 has almost no silver solvent in it, so grain boundaries stay where the exposure put them, and a bath this dilute exhausts locally where the exposure was heaviest, which is the mechanism behind adjacency effects. The formulary page reaches the same position by the same route and marks it the same way.

Sources:E. J. Wall, edited by F. J. Mortimer, 1912§ Development and Developers - Paramidophenol, the concentrated one-solution formula and the note that the developer is stainless and keeps well

Argued in:Rodinal type, image characteristics

Effect on film speed

The question Does the maker publish an exposure change for using this developer, and what is the figure?

The scale: Effect on film speed, ordered

What the maker publishes about the exposure the film needs in this developer. Silence is not a point on this scale: it is an unscored cell.

1. 1Published lossThe maker publishes an exposure increase, and the cell gives the figure.
2. 2No loss claimedThe maker states full or normal emulsion speed for this developer.

Where a cell is empty The maker publishes neither a claim of full speed nor a penalty for this formula. That silence is not a claim of full speed and the course does not turn it into one: an unstated speed effect is unknown, not zero.

D-76the borax standard

No loss claimedposition 2 of 2stated by the source

Full emulsion speed is the claim Kodak has made for this formula since the 1920s, and the borax is in the bath for it: enough alkali to develop briskly without the fog and the speed loss that a carbonate developer of the same era brought with it. No exposure compensation is published for D-76 anywhere in the corpus.

Sources:Kodak Alaris Inc., 2017§ The opening description · Eastman Kodak Company, 1928§ Borax and the high sulphite of D-76; the reduction-potential ranking of the developing agents

Argued in:D-76, image characteristics

D-23two ingredients

No loss claimedposition 2 of 2stated by the source

Normal emulsion speed is Kodak's own claim for D-23 in the 1949 handbook, which is worth noticing because the formula has no alkali in it beyond the sulfite itself and develops in about eighteen minutes at 18 degrees C. The speed is bought with time rather than with activity.

Sources:Kodak Limited, 1949§ Kodak formula D-23, with its description and its development time

Argued in:D-23, image characteristics

D-25minimum grain

Published lossposition 1 of 2stated by the source

Kodak publishes the penalty with the formula: this developer requires a 50 to 100 per cent increase in exposure, which is between half a stop and a full stop. It is the only figure of its kind in this column, and it is what makes the minimum-grain claim usable - a grain claim with no stated cost cannot be compared with anything.

Sources:Kodak Limited, 1949§ Kodak formula D-25, its exposure warning

Argued in:D-25, image characteristics

DK-20thiocyanate

Not established

Kodak publishes no exposure increase for DK-20, unlike D-25 on the facing page of the same handbook. The absence is suggestive and it is not a claim of full speed, and the formulary page refuses to make it one. What would settle it is a Kodak statement of the kind D-76 and D-23 carry, or a measured speed point once Part XIII's practical work is performed.

Sources:Kodak Limited, 1949§ Kodak formula DK-20; Kodak formula D-25 and its exposure warning

Argued in:DK-20, image characteristics

DK-50brisk, general

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-19bhigh contrast

Not established

No manufacturer figure exists, and the formula carries 4.0 g of potassium bromide per litre, which is a reason to expect a raised threshold rather than an unchanged one. The course records the expectation on the page and refuses to place it on a scale, because a restrainer's effect on the speed point is a measurement and not a deduction.

Sources:Kodak Limited, 1949§ Kodak formula D-19b and its metric column

Argued in:D-19b, image characteristics

Beutlerhigh acutance

Not established

No source read for this formula publishes an effective film speed, a speed increase or a speed loss. The one instruction that looks like a speed statement is not one: Windisch's direction for a film faster than 16 ASA is to use a lesser quantity of solution B, which changes the activity of the bath and says nothing about the exposure the film needs, and he does not say how much less.

Sources:Hans Windisch, 1956§ The note that medium-speed films require a lesser quantity of solution B, and the definition of low-speed film as 8 to 16 ASA

Argued in:Beutler, behaviour

PMKstaining

Not established

The one maker who addresses speed says both things. BERGGER's opening paragraph states that the stain increases the sensitivity of the film and its printing qualities; its own time and temperature chart three pages later gives exposure indices below box speed for all nine films in it, by between a third of a stop and a whole one. Photographers' Formulary's indices point the same way and slightly less far, with T-Max 400 the only film given its box speed outright. The two statements can be reconciled - a stain that adds shadow density can raise printing speed while the maker still recommends generous exposure - but that reconciliation is the course's and not the maker's, and no measured speed figure for PMK exists in any document the course has read.

Sources:BERGGER, 2020§ PMK properties, the sensitivity sentence; the Time / Temp Chart and its ISO column · Photographers' Formulary Inc.§ DEVELOPMENT TIMES, the exposure indices at 70 and 80 degrees F

Argued in:PMK, image characteristics

Rodinal typeWall, 1924

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Contrast

The question What gradient does the maker publish this developer for, at its own time and temperature?

The scale: Contrast, ordered

The gradient the formula was designed to give at its own published time and temperature, in the maker's words.

1. 1SoftThe maker's own word is soft-working: a long, gentle scale with restrained highlights.
2. 2NormalA pictorial negative from a normal subject, which is what the maker publishes it for.
3. 3HighLine, copy, X-ray or scientific record. High contrast is the formula's stated purpose.

Where a cell is empty The maker gives the formula no contrast description at all, and no time-and-temperature series exists in the course's corpus from which to place it.

D-76the borax standard

Normalposition 2 of 3stated by the source

A pictorial negative of normal contrast over a long density range, which is what Kodak publishes it for and what the 1949 handbook's own heading calls a low-contrast developer by comparison with the copying baths beside it. The borax buffer is what holds the gradient steady as the bath is used.

Sources:Kodak Alaris Inc., 2017§ The opening description; development-time tables at full strength and 1:1 · Kodak Limited, 1949§ Some Kodak packed developers

Argued in:D-76, image characteristics

D-23two ingredients

Softposition 1 of 3stated by the source

Soft-working is Kodak's own word for D-23 in the handbook that prints it. With no alkali beyond the sulfite and no hydroquinone to build density late, the bath produces a long gentle scale with restrained highlights, and it is the softest of the six at its own published time and temperature.

Sources:Kodak Limited, 1949§ Kodak formula D-23, with its description

Argued in:D-23, image characteristics

D-25minimum grain

Softposition 1 of 3stated by the source

D-23 with bisulfite added, which lowers the pH further: the same soft-working design taken one step further, and lower in contrast than D-23 at the same time and temperature. The formulary page states the comparison and the direction, and Kodak's own reason for the bisulfite is the grain rather than the contrast.

Sources:Kodak Limited, 1949§ Kodak formula D-25 and Kodak formula D-23, with their descriptions and development times

Argued in:D-25, image characteristics

DK-20thiocyanate

Normalposition 2 of 3stated by the source

Normal is Kodak's own word for DK-20 in the packed-developer list, which is the point of the formula: an extra-fine-grain bath that does not also cost you the gradient, unlike the two soft-working baths that reach fine grain by lowering activity.

Sources:Kodak Limited, 1949§ Some Kodak packed developers; Kodak formula DK-20

Argued in:DK-20, image characteristics

DK-50brisk, general

Normalposition 2 of 3stated by the source

Normal, and the only one of the six for which Kodak publishes how to move it: the handbook's own note says the Kodalk may be varied to raise or lower contrast. That makes DK-50 the adjustable case in this column rather than simply a middle one, and the formulary page carries Kodak's instruction.

Sources:Kodak Limited, 1949§ Kodak formula DK-50, with its note on varying the Kodalk

Argued in:DK-50, behaviour

D-19bhigh contrast

Highposition 3 of 3stated by the source

High contrast is the formula's stated purpose rather than a side effect: 48 g of anhydrous carbonate a litre, 8.8 g of hydroquinone to build density late, and 4 g of potassium bromide to keep the toe clean while it does. It is published for high-contrast dish and tank development, and the same handbook prints D-76 and D-23 for everything else.

Sources:Kodak Limited, 1949§ Kodak formula D-19b, its description and its metric column

Argued in:D-19b, image characteristics

Beutlerhigh acutance

Not established

No source gives this bath a gradient. Windisch's times are 7 to 10 minutes at 18 degrees C "according to gradation", which hands the gradient to the worker rather than describing one, and the later printings widen the times to 8 to 15 minutes at 20 degrees C without adding a description. The nearest thing to a contrast statement in the corpus belongs in the compensating column and is argued there.

Sources:Hans Windisch, 1956§ The development time of 7 to 10 minutes at 65 degrees F and 18 degrees C according to gradation · Geoffrey Crawley (editor), 1972§ The developing times of 8 to 15 minutes at 68 degrees F and 20 degrees C

Argued in:Beutler, behaviour

PMKstaining

Not established

Neither maker publishes a gradient, a contrast index or a curve. What they publish instead are claims about where the gradient goes: BERGGER's detailed highlights, and the Formulary's flexibility for Zone System plus and minus development, which is a statement that the contrast can be moved rather than a statement of where it sits. A developer whose density is the sum of a silver density and a stain density would in any case need to say which of the two a published gradient was measured through, and neither sheet says.

Sources:Photographers' Formulary Inc.§ The opening paragraph - flexibility for zone system Plus and Minus development · BERGGER, 2020§ PMK properties - the claim of detailed highlights

Argued in:PMK, image characteristics

Rodinal typeWall, 1924

Not established

Wall's words for this developer are energetic, for the class, and clean-working, for the formula, and neither is a gradient. No source the course holds publishes a contrast index, a gamma or a characteristic curve for any developer of this type. What the corpus does hold is a time-and-temperature grid - Munkman's stand-development table for the proprietary rodinal at 1:100, with separate columns for portrait, architecture and landscape - and that is a table of subjects rather than of gradients, for a product rather than for this formula.

Sources:E. J. Wall, F.C.S., F.R.P.S., 1924§ Development, pages 80 to 83 - stand development and the Rodinal (Munkman) time-and-temperature table at 1:100

Argued in:Rodinal type, behaviour

Compensating

The question Does the maker state that this developer is compensating, meaning that it exhausts locally in the highlights and holds them back?

This column is empty on purpose, and it is the clearest single demonstration of what the product is for. Compensating is one of the sixteen properties the brief asks a matrix to compare; six developers here plainly differ in it; and the honest score for every one of them is nothing at all.

The scale: Kind of claim, a set of alternatives with no ordering

For an axis where the only honest answer is who says so: a claim published by the maker, or a behaviour this course has measured for itself.

1. Published by the makerThe maker states it in a document this course holds.
2. Measured by the courseThis course measured it, and the page carries the method and the numbers.

Where a cell is empty No document in this course's corpus states that any of these developers is compensating. D-23 is widely described that way, and its own page records the description and refuses it, because the description is not Kodak's. What would settle it is a manufacturer statement or a measured pair of curves at two subject luminance ranges, and this course has neither.

D-76the borax standard

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-23two ingredients

Not established

D-23 is very widely described as a compensating developer, on the reasoning that its low activity and absent buffer let it exhaust locally in the highlights. The course has found no manufacturer statement to that effect and does not make the claim, and it will not be scored here on the strength of how often it is repeated. What would settle it is a Kodak statement, or a measured pair of curves from two subject luminance ranges.

Sources:Kodak Limited, 1949§ Kodak formula D-23 and its description, which uses the phrase soft-working and not compensating

Argued in:D-23, image characteristics

D-25minimum grain

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

DK-20thiocyanate

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

DK-50brisk, general

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-19bhigh contrast

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Beutlerhigh acutance

Not established

Nobody calls this developer compensating and one source describes the behaviour that usually earns the word. Anchell and Troop find that Beutler-type developers tend to compress tones excessively, especially where the negative is enlarged with a cold light head. A compressed scale seen from the print end is the same phenomenon as compensation seen from the negative end, but it is an experienced practitioner's assessment of a class rather than a maker's claim about this formula, and it is offered as a caution rather than as a property. The course scores neither on the strength of it.

Sources:Stephen G. Anchell and Bill Troop, 1998§ The acutance chapter - the caution that Beutler-type developers tend to compress tones excessively, especially with a cold light head

Argued in:Beutler, image characteristics

PMKstaining

Not established

Neither maker uses the word, and one of them comes close enough to be worth recording. The Formulary's design list includes flexibility for minus development and BERGGER claims detailed highlights, which is what a reader looking for compensation would seize on; neither is a statement that the bath exhausts locally in the highlights and holds them back, and neither publishes the pair of curves at two subject luminance ranges that would show it. A very dilute one-shot bath is the kind of developer in which local exhaustion is plausible, and plausible is not a score.

Sources:Photographers' Formulary Inc.§ The opening paragraph on what the formula is constituted to achieve

Argued in:PMK, image characteristics

Rodinal typeWall, 1924

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Shelf life

The question What keeping figures does the maker publish for the stock solution and for the bath in use?

The scale: Keeping, ordered

The longest keeping figure the maker publishes for the solution in a full, closed bottle. The cell gives the shorter working figures with it.

1. 1HoursPublished in hours: a bath made for the session it is used in.
2. 2DaysPublished in days.
3. 3WeeksPublished in weeks.
4. 4MonthsPublished in months in a full stoppered bottle; the half-filled figure is always shorter and is given in the cell.
5. 5IndefiniteThe maker's own word. It keeps until something contaminates it.

Where a cell is empty The document carrying the formula publishes no keeping table for it. Keeping is a measurement rather than a deduction, and an unmeasured developer's keeping cannot be read off its ingredient list.

D-76the borax standard

Monthsposition 4 of 5stated by the source

Six months in a full stoppered bottle, two months half-filled, one month in a covered tank and 24 hours in a tray. The pair of bottle figures is the whole lesson: a half-empty bottle is a slow oxidation cell, and Kodak publishes the same four figures in 1949 and again in 2017, which is a rare piece of corroboration between two independent printings sixty-eight years apart.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions · Kodak Alaris Inc., 2017§ Storage life and capacity

Argued in:D-76, storage

D-23two ingredients

Monthsposition 4 of 5stated by the source

Six months full, two months half-filled, one month in a tank, 24 hours in a dish, on the 1949 keeping table. The half-full figure is where these developers separate, and D-23 sits with the majority at two months rather than with D-19b at three.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:D-23, storage

D-25minimum grain

Monthsposition 4 of 5stated by the source

The same row as D-23 on the same table: six months full, two half-filled, a month in a tank, 24 hours in a dish. The bisulfite that distinguishes the formula makes no difference the keeping table records, which is worth knowing because an acid salt in a sulfite bath might have been expected to.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:D-25, storage

DK-20thiocyanate

Monthsposition 4 of 5stated by the source

Six months full, two half-filled, one month in a tank, 24 hours in a dish. The tank figure carries the table's own footnote that the useful life is greatly increased by replenishment, which is the difference between a keeping figure and a working life and the reason the two are not the same column.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:DK-20, storage

DK-50brisk, general

Monthsposition 4 of 5stated by the source

Six months full, two half-filled, one month in a tank, 24 hours in a dish - the ordinary row. What sets DK-50 apart on this table is not its keeping but its deep-tank capacity of 48 sheets, which its page states is the only figure that high with no replenisher footnote against it.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:DK-50, storage

D-19bhigh contrast

Monthsposition 4 of 5stated by the source

Six months full and three months half-filled, which is the best half-full figure of any negative developer on the 1949 table; a month in a tank and 24 hours in a dish. The extra month half-full goes with the highest sulfite-to-agent ratio in this column, and Kodak does not explain it.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:D-19b, storage

Beutlerhigh acutance

Not established

Windisch's whole published statement is that the two stock solutions in well-stoppered bottles "will keep for a long time", which is not a figure and cannot be turned into one. What can be said is why they keep: the developing agent never meets the alkali until the moment of use, which is the general practice Kodak Limited records for developers susceptible to aerial oxidation. The working bath has no keeping time because no source expects anyone to keep it.

Sources:Hans Windisch, 1956§ The keeping statement for the two stocks · Kodak Limited, 1949§ Storage of developer solutions - developers susceptible to aerial oxidation divided into two or three solutions with the developing agent kept separate from the alkali

Argued in:Beutler, storage

PMKstaining

Indefiniteposition 5 of 5stated by the source

The maker's own word, and it is the strongest keeping claim in this matrix by a wide margin: Photographers' Formulary gives the stock solutions an indefinite shelf life and says partially filled stoppered bottles will last for years, and BERGGER puts ten years on half-filled ones. Set that against the Kodak keeping table, where every developer's figure halves when the bottle is half empty, and the difference is the point: A solution is acid, and oxidation progresses less readily in acid than in alkaline solution. The mixed working bath is the opposite extreme - one hour in an open vessel by BERGGER's account and "use immediately" by the Formulary's.

Sources:Photographers' Formulary Inc.§ LIFE OF THE STOCK SOLUTIONS · BERGGER, 2020§ Preparation and Conservation; Use - working-solution life

Argued in:PMK, storage

Rodinal typeWall, 1924

Not established

Wall's 1912 entry says the developer keeps well in single concentrated solution and gives no period at all, and that is the whole of the published evidence. The bottle also has a property no keeping figure would capture: Wall's instruction is to leave some of the base undissolved on purpose and to add more soda solution if more crystallises out, so a bottle of this concentrate is meant to have solid at the bottom, and the usual test of whether a developer has kept - is it still clear - does not apply to it. Date the bottle and test it against a control strip.

Sources:E. J. Wall, edited by F. J. Mortimer, 1912§ Development and Developers - Paramidophenol, the note that the developer keeps well in concentrated solution · E. J. Wall, F.C.S., F.R.P.S., 1924§ Developers, page 109 - the instruction that it is very important to leave some undissolved

Argued in:Rodinal type, storage

One-shot or reusable

The question How does the maker publish this bath being worked: discarded, reused to a capacity, or replenished?

The scale: One-shot or reusable, a set of alternatives with no ordering

How the maker publishes the bath being used: discarded after one batch, used again, topped up with a replenisher, or offered both ways.

1. One-shotMixed, used once and discarded, on the maker's instruction.
2. ReusableUsed again until its published capacity is reached.
3. ReplenishedKept at working strength by adding a published replenisher, which has its own formula.
4. EitherThe maker publishes both ways of working it, usually at two dilutions.

Where a cell is empty The maker publishes no working practice for the bath.

D-76the borax standard

Eitherstated by the source

Kodak publishes both ways and they are different developers in use. At stock strength it is a reusable tank bath, replenishable with D-76R, and the replenished capacity is 120 rolls per US gallon against 16 unreplenished - a factor of seven and a half. At 1+1 it is one-shot and Kodak is emphatic: dilute just before use, discard after one batch, never replenish.

Sources:Kodak Alaris Inc., 2017§ Storage life and capacity; replenishment rates and replenished capacity

Argued in:D-76, behaviour

D-23two ingredients

Eitherstated by the source

The 1949 handbook gives dish and deep-tank capacities for it and prints D-25R as a replenisher for D-23 and D-25 together, so the bath can be worked as a reusable tank developer or discarded after a session. The handbook publishes no dilution at all for D-23, so the choice is about reuse and not about strength.

Sources:Kodak Limited, 1949§ Kodak formula D-23; Kodak formula D-25R, headed Replenisher for Kodak developers D-23 and D-25; Keeping properties and useful life of solutions

Argued in:D-23, behaviour

D-25minimum grain

Eitherstated by the source

As D-23, and by the same replenisher: D-25R is headed as the replenisher for both. The dish and deep-tank capacities are the lowest of the six at 20 and 30 sheets of 8 by 10 inches per 160 imperial fluid ounces, which is the practical cost of working the softest and most solvent-heavy bath here.

Sources:Kodak Limited, 1949§ Kodak formula D-25R; Keeping properties and useful life of solutions

Argued in:D-25, behaviour

DK-20thiocyanate

Replenishedstated by the source

Kodak prints DK-20R specifically to maintain the volume and activity of a DK-20 tank, gives a deep-tank rate of about five gallons of replenisher per thousand rolls, and sets the limit at which replenishment stops working: additions continue until a quarter of the original developer has been replaced. A bath with a published replenisher and a published replacement limit is being sold as a replenished bath.

Sources:Kodak Limited, 1949§ Kodak formula DK-20R, headed Replenisher for Kodak developer DK-20 to maintain volume and activity of tank developer

Argued in:DK-20, behaviour

DK-50brisk, general

Reusablestated by the source

The 1949 table gives DK-50 48 sheets of 8 by 10 inches in a deep tank per 160 imperial fluid ounces, and its page states that this is the only figure that high carrying no replenisher footnote - which makes it the one developer of the six that reaches its working life without a second formula behind it. Two pages of this course disagree about which deep-tank figure is the table's highest: DK-50's page calls its 48 sheets the highest deep-tank figure of any developer on the table, and D-19b's calls its own 72 the highest figure on the whole developer table. Both cannot be right, and the matrix records the disagreement rather than quietly picking one.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:DK-50, behaviour

D-19bhigh contrast

Replenishedstated by the source

Kodak prints D-19bR as its replenisher, and the unreplenished capacities are already high: 36 sheets of 8 by 10 inches in a dish against 24 for D-76, D-23, DK-20 and DK-50, and 72 in a deep tank against their 36, 36, 36 and 48. A high-contrast bath used for volume record work is exactly the case a replenisher exists for.

Sources:Kodak Limited, 1949§ Kodak formula D-19bR, headed Replenisher for Kodak D-19b developer; Keeping properties and useful life of solutions

Argued in:D-19b, behaviour

Beutlerhigh acutance

One-shotstated by the source

Haist classifies it by use rather than by ingredient: typical high-definition one-use developers are those of Beutler and Crawley. No source publishes a replenisher, a capacity or a keeping time for the mixed bath, and with 0.83 g of metol in a litre there is very little agent to exhaust - which is the mechanism the sharpness depends on and also the reason a second film through the same litre is not an experiment worth running.

Sources:Grant Haist, 1979§ High-definition developers - the sentence that typical high-definition one-use developers are those of Beutler and Crawley

Argued in:Beutler, behaviour

PMKstaining

One-shotstated by the source

"PMK is a one-shot developer" is the Formulary's own sentence, and both makers back it with a minimum quantity rather than a capacity - which is the same instruction pointing the other way. The two floors do not agree: the Formulary sets 300 mL per 80 square inches of film, glossed as one 36-exposure roll or four 4 by 5 sheets, and BERGGER sets 1,000 square centimetres of film per litre, which asks for about 1.7 times as much developer for the same film. The course prints both and takes neither as the other's correction.

Sources:Photographers' Formulary Inc.§ CAPACITY OF PMK; WORKING SOLUTION OF PMK · BERGGER, 2020§ Use - capacity, working-solution life and temperature range

Argued in:PMK, behaviour

Rodinal typeWall, 1924

Not established

Wall states no capacity for this formula and no working practice for the bath after it has been used, so there is nothing to score. What he does say belongs to the class rather than to the formula: a tank of dilute developer is, as a rule, so oxidised at the end of development as to be useless for a second time. Foma publishes a capacity for its own manufactured equivalent - 250 mL sufficient for 25 rolls or up to 62 sheets of 13 by 18 cm at 1+25 or 1+50 - and that is a figure for a different product, made to a strength its maker controls and does not publish.

Sources:E. J. Wall, F.C.S., F.R.P.S., 1924§ Development, pages 80 to 83 - stand development and the oxidation of a dilute tank at the end of development · FOMA BOHEMIA spol. s r.o., 2023§ FOMADON R 09 - the developing capacity per package

Argued in:Rodinal type, behaviour

Cost

The question What does a litre of this developer cost to mix from raw chemicals, on the dated UK prices behind the laboratory planner?

The bands are the course's own relative ones and no money threshold defines them, so every cell here shows the arithmetic it rests on: the price file's own pack prices, divided down to the dose the formula calls for.

The scale: Cost, ordered

The course's relative cost band for mixing a litre from raw chemicals, on the dated UK prices in the price file behind the laboratory planner. The bands are relative and the course defines no money threshold for them, so every cell gives the priced subtotal it rests on and names the ingredients the price file could not price.

1. 1£The cheapest band: bulk photographic chemicals, in doses of a few grams to a hundred grams a litre.
2. 2££The ordinary band. Several bulk chemicals, or one bought in a small jar at a laboratory price.
3. 3£££One ingredient dominates the cost, and it is usually a silver salt.
4. 4££££A noble metal at working strength. The chemistry is a significant purchase in itself.

Where a cell is empty One or more ingredients are not in the course's price file, so the subtotal would be a floor rather than a figure and the band cannot be stated. Naming the missing prices is the useful thing this cell can do.

D-76the borax standard

£position 1 of 4an inference by this course

All four ingredients are priced. Per litre: 2 g of metol at 16.20 for 50 g is 0.65; 100 g of anhydrous sulfite at 13.68 to 19.98 the kilogram is 1.37 to 2.00; 5 g of hydroquinone at 11.89 for 50 g is 1.19; 2 g of borax at 9.98 for 200 g is 0.10. A litre is therefore about 3.31 to 3.94 in sterling, which is less than one roll of 35 mm film in the same file.

Sources:The course price file, GBP, checked 2026-09-07§ metol (50 g); sodium-sulfite (1 kg, anhydrous); hydroquinone (50 g); borax (200 g, decahydrate); film-35mm (one 35 mm roll, 36 exposures)UK retail listings read in one session, inclusive of VAT and exclusive of delivery. Ranges to plan against, not quotations.

Argued in:The laboratory planner and its price file

D-23two ingredients

£position 1 of 4an inference by this course

Two ingredients, both priced. Per litre: 7.5 g of metol is 2.43, and 100 g of anhydrous sulfite is 1.37 to 2.00, so about 3.80 to 4.43 in sterling. It is dearer than D-76 despite having half the ingredients, because nearly four times as much metol is doing all the work alone - which is the cost of a formula you can understand in one line.

Sources:The course price file, GBP, checked 2026-09-07§ metol (50 g); sodium-sulfite (1 kg, anhydrous)

Argued in:The laboratory planner and its price file

D-25minimum grain

£position 1 of 4an inference by this course

All three ingredients are priced now that the bisulfite is in the file, so this is a total rather than the floor it was. D-23's two come to 3.80 to 4.43 the litre, and the 15 g of sodium bisulfite that makes this D-25 rather than D-23 adds 0.60 at 40.00 the kilogram: about 4.40 to 5.03 in sterling. Sixty pence buys the smaller grain and the published exposure penalty that comes with it, which is the cheapest trade-off in this column and not the smallest one.

Sources:The course price file, GBP, checked 2026-09-07§ metol (50 g); sodium-sulfite (1 kg, anhydrous) · The course price file, GBP, checked 2026-09-07§ sodium-bisulfite (1 kg)Added to the price file on 7 September 2026. The listing is titled for sodium bisulfite and sodium metabisulfite at once and does not say which is in the tub; D-25 specifies the bisulfite.

Argued in:The laboratory planner and its price file

DK-20thiocyanate

Not established

Two of the five ingredients are unpriced. The metol, sulfite and bromide come to about 3.04 to 3.67 the litre, and the price file holds no figure for either potassium thiocyanate or sodium metaborate tetrahydrate. Both are now named in that file's gaps, which is an improvement on the silence this cell recorded when it was written and is not a price: both are bought by the jar rather than by the gram, so the unpriced part is not a rounding error on a first purchase, and the course will not put a band on it.

Sources:The course price file, GBP, checked 2026-09-07§ metol (50 g); sodium-sulfite (1 kg, anhydrous); potassium-bromide (250 g)

Argued in:The laboratory planner and its price file

DK-50brisk, general

Not established

Four of the five ingredients are priced and come to about 1.87 to 2.06 the litre, the cheapest priced subtotal in this column. The fifth, 10 g of sodium metaborate tetrahydrate, is still not in the price file, though it is now named in that file's gaps, and it is the largest single dose of unpriced material in the whole matrix. A band stated on the priced four alone would make this the cheapest developer here on the strength of the one ingredient nobody costed.

Sources:The course price file, GBP, checked 2026-09-07§ metol (50 g); sodium-sulfite (1 kg, anhydrous); hydroquinone (50 g); potassium-bromide (250 g)

Argued in:The laboratory planner and its price file

D-19bhigh contrast

£position 1 of 4an inference by this course

All five are priced. Per litre: 2.2 g of metol is 0.71; 72 g of anhydrous sulfite is 0.99 to 1.44; 8.8 g of hydroquinone is 2.09; 48 g of anhydrous carbonate at 7.20 for 500 g is 0.69; 4 g of potassium bromide at 23.00 for 250 g is 0.37. About 4.85 to 5.30 in sterling, the dearest of the four that can be costed, and the hydroquinone is why.

Sources:The course price file, GBP, checked 2026-09-07§ metol (50 g); sodium-sulfite (1 kg, anhydrous); hydroquinone (50 g); sodium-carbonate (500 g, anhydrous); potassium-bromide (250 g)

Argued in:The laboratory planner and its price file

Beutlerhigh acutance

£position 1 of 4an inference by this course

All three ingredients are priced, and the answer is not comparable with the rest of this column until the dilution is taken into account. A litre of working bath at 1+1+10 carries 0.83 g of metol at 0.27, 4.17 g of anhydrous sulfite at 0.06 to 0.08 and 4.17 g of anhydrous carbonate at 0.06: about 0.39 to 0.41 in sterling, and about 0.46 to 0.50 at the stronger 1+1+8. That is a tenth of what a litre of D-76 or D-23 costs in the tank, because those two are used at stock strength and this one is a twelfth as concentrated a solution. A litre of each stock, which is what you actually mix, comes to about 4.64 to 4.96 for the pair and makes twelve litres of developer.

Sources:The course price file, GBP, checked 2026-09-07§ metol (50 g); sodium-sulfite (1 kg, anhydrous); sodium-carbonate (500 g, anhydrous)

Argued in:The laboratory planner and its price file

PMKstaining

Not established

Three of the four ingredients are now priced and the fourth is not, so this is a floor and not a band. A litre of working developer at 1+2+100 carries 0.971 g of pyrogallol at 0.87, 0.097 g of metol at 0.03 and 0.194 g of sodium bisulfite at under a penny: about 0.91 in sterling, of which the pyrogallol is ninety-six per cent. The missing ingredient is 5.83 g a litre of sodium metaborate tetrahydrate, which the price file names among its gaps and which is also the ingredient that makes DK-20 and DK-50 unscoreable in this same column. What can be said without it is that a batch of A solution carries about 22.50 of pyrogallol and makes about 26 litres of working developer.

Sources:The course price file, GBP, checked 2026-09-07§ metol (50 g) · The course price file, GBP, checked 2026-09-07§ pyrogallol (50 g); sodium-bisulfite (1 kg)Added to the price file on 7 September 2026. Sodium metaborate in either hydrate is unpriced and is named in the file's gaps.

Argued in:The laboratory planner and its price file

Rodinal typeWall, 1924

Not established

The only subject in this column with no priced ingredient at all. Para-aminophenol hydrochloride, potassium metabisulphite and sodium hydroxide are all absent from the price file, and all three are named in its gaps; the concentrate carries 50, 150 and 215 grams of them respectively to the litre, so there is no part of the formula small enough for the absence not to matter. What the file can now say is what the class costs bought rather than mixed: a manufactured p-aminophenol one-shot concentrate is 6.00 for 100 mL and 12.00 for 250 mL. That prices the bottle and not the formula, and the axis asks about mixing from raw chemicals.

Sources:The course price file, GBP, checked 2026-09-07§ p-aminophenol-concentrate (100 or 250 mL of p-aminophenol liquid concentrate)Added to the price file on 7 September 2026. Cited to show what the file does hold for this class; the three raw chemicals the formula needs are named in the file's gaps and none is priced.

Argued in:The laboratory planner and its price file

Complexity

The question What does mixing and working this developer actually demand: how many solids, in what order, at what temperature, and is there a second solution to make?

The scale: Complexity to make and work, ordered

What mixing and using the formula actually demands: how many things are weighed, whether order and temperature matter, and whether the bath has to be made in parts or ripened before use.

1. 1SimpleA handful of solids into water in a stated order, at room temperature, used straight away.
2. 2ModerateSeveral solids, an order that matters and a stated dissolving temperature, or a stock that is diluted before use.
3. 3InvolvedTwo or more solutions to mix separately and combine correctly, a hot bath, or a ripening period before the formula works.
4. 4SpecialistNeeds equipment, control or handling beyond a domestic laboratory, and the course says so on the page.

Where a cell is empty The source publishes no mixing instruction, so what the formula demands of the person making it is not established.

D-76the borax standard

Moderateposition 2 of 4stated by the source

Four solids in an order that is a solubility problem rather than a convention - metol before sulfite, because metol is only slightly soluble in a sulfite solution with no alkali in it - and Kodak's 1928 directions split the sulfite in two and specify water at about 52 and 71 degrees C. Nothing here is beyond a kitchen, and nothing here forgives the wrong order.

Sources:Eastman Kodak Company, 1928§ Directions for mixing D-76 · Kodak Limited, 1949§ Making up solutions - the order of dissolving and the rule for Elon

Argued in:D-76, mixing

D-23two ingredients

Simpleposition 1 of 4stated by the source

Two solids into warm water, metol first, then the sulfite, then cold water to volume. It is the simplest formula in this reference and the one where the order matters most: the metol is the developer, there is no alkali to bring undissolved powder back, and a bath with a haze that will not clear is not D-23 and no development time will fix it.

Sources:Kodak Limited, 1949§ Kodak formula D-23; Making up solutions - the order of dissolving and the rule for Elon

Argued in:D-23, mixing

D-25minimum grain

Simpleposition 1 of 4stated by the source

Three solids, and one specific instruction on top of the general rule: Kodak's 1949 note on making up solutions says that where sodium bisulfite appears it goes in with the sulfite. So metol into warm water first, then the sulfite and the bisulfite together, then cold water to volume. The metol-first rule is more pressing here than in D-23, because the bisulfite makes the solution less alkaline still.

Sources:Kodak Limited, 1949§ Kodak formula D-25; Making up solutions - the note on sodium bisulfite

Argued in:D-25, mixing

DK-20thiocyanate

Moderateposition 2 of 4stated by the source

Five solids in Kodak's printed order, with one relaxation the handbook states outright: potassium bromide has no action on the developing agents, so where it goes in is immaterial. The metaborate is roughly eight times as soluble as borax at room temperature, so unlike D-76 there is no hot-water step for the alkali. What raises it above simple is the thiocyanate, which must be stored well away from every acid in the darkroom.

Sources:Kodak Limited, 1949§ Kodak formula DK-20; Making up solutions - the order of dissolving and the note that the stage at which bromide is added is immaterial

Argued in:DK-20, mixing

DK-50brisk, general

Simpleposition 1 of 4stated by the source

Five solids, but the two things that make D-76 fiddly are both absent: 30 g of sulfite goes into solution quickly in a small volume, and the metaborate needs no hot water. The one trap is the alkali itself - Kodalk is the tetrahydrate, most of its mass is water of crystallisation, and weighing a different hydrate against this formula throws out the one ingredient Kodak publishes an instruction for varying.

Sources:Kodak Limited, 1949§ Kodak formula DK-50, with its dissolving instruction and its note on varying the Kodalk

Argued in:DK-50, mixing

D-19bhigh contrast

Moderateposition 2 of 4stated by the source

Five solids in the printed order, and the difficulty is not the dissolving but the salts. The handbook prints its main column in crystalline salts and its parentheses in anhydrous ones, and both the sulfite and the carbonate are two different substances at two different quantities - 144 g of the sulfite heptahydrate or 72 g anhydrous, 130 g of carbonate decahydrate or 48 g anhydrous. Take one column all the way down or the bath is not D-19b.

Sources:Kodak Limited, 1949§ Kodak formula D-19b and its two columns; Making up solutions - crystals at two and a half times the anhydrous quantity

Argued in:D-19b, mixing

Beutlerhigh acutance

Moderateposition 2 of 4stated by the source

Three solids and two bottles, and the two bottles are the formula rather than a convenience: the agent is kept away from the alkali so that stock A keeps. Metol goes into warm water before the sulfite, because this is the one formula here whose stock A is a sulfite solution with no alkali at all to bring undissolved powder back. What keeps it below the involved band is that combining the two is a dilution and not an operation - equal volumes of A and B and eight or ten of water, poured at the tank - with no temperature to hit and no endpoint to judge.

Sources:Kodak Limited, 1949§ Making up solutions - the rule that Elon is dissolved first because it is only slightly soluble in sulphite solutions without alkali · Hans Windisch, 1956§ The two stock solutions and their make-up water, and the instruction to add 50 cc of A and 50 cc of B to 500 cc of water

Argued in:Beutler, mixing

PMKstaining

Involvedposition 3 of 4stated by the source

Two stock solutions to make separately and combine correctly, which is the definition of this band, and three further demands on top of it. Distilled water is an instruction and not a preference - the Formulary capitalises MUST for B solution, on the grounds that 30 per cent metaborate will throw a precipitate in impure water. The preservative is split around the metol, a pinch before and the rest after, which is a 1928 Kodak rule reprinted on a 1990s kit sheet. And the pyrogallol goes in last, under ventilation, because it is the ingredient that oxidises fastest and the dustiest thing on the bench.

Sources:Photographers' Formulary Inc.§ MIXING THE STOCK SOLUTIONS; WORKING SOLUTION OF PMK · Eastman Kodak Company, 1928§ Chapter X - the general rule that the preservative is dissolved first, the exception for Elon, and the practice of dissolving a portion of the sulphite before the Elon and the remainder after

Argued in:PMK, mixing

Rodinal typeWall, 1924

Involvedposition 3 of 4stated by the source

Two solutions made separately, combined in one direction only, and finished at an endpoint judged by eye. The water is boiled and cooled to drive the air out of it; 215 g of caustic soda is dissolved in 500 mL of cold water and left to cool; then 340 to 350 mL of that is stirred into the aminophenol solution, where the base first precipitates and then redissolves, and the instruction is to stop just short - enough soda to nearly dissolve the precipitate, with some deliberately left undissolved. Nothing else in this matrix asks the maker to judge a stopping point rather than weigh one.

Sources:E. J. Wall, F.C.S., F.R.P.S., 1924§ Developers, pages 108 and 109 - One solution, similar to rodinal (Ermen), with its caustic soda solution and the quantity to be added · Eastman Kodak Company, 1928§ The caustic alkalis and the rule that both are dissolved in cold water; formula D-9 and the warning about hot water

Argued in:Rodinal type, mixing

Safety classification

The question What is the course's hazard-assessed level for this formula, and which substance sets it?

The scale: Safety classification, ordered

The course's own hazard-assessed classification for the formula or process, from the safety library. The cell names the substance that sets it.

1. 1Level ADomestic-scale care. No specialist control is required by the substances themselves.
2. 2Level BGloves, eye protection and ventilation as stated; a sensitiser, an irritant or a dust that must not be breathed.
3. 3Level CA serious hazard with a named control; restricted procedures, and never a first session.
4. 4Level DStudied and never performed at home. The course gives the chemistry, the history and the hazards, and no procedure.

Where a cell is empty The formula has not been classified. Every formula in this course carries a level, so an empty cell here would be a fault rather than a finding.

D-76the borax standard

Level Bposition 2 of 4stated by the source

Three of the four ingredients put it past Level A on their own. Metol is a skin sensitiser and sensitisation is not reversible; hydroquinone carries a Danger classification with suspected carcinogenicity and mutagenicity and causes serious eye damage; borax is classified for reproductive toxicity, which is the only reason a substance this mild is not a Level A material. The hazardous part of the job is the dry powders on the balance, not the bath.

Sources:National Center for Biotechnology Information§ GHS classification - skin sensitisation · National Center for Biotechnology Information§ GHS classification - Danger, serious eye damage, suspected carcinogenicity and mutagenicity · National Center for Biotechnology Information§ GHS classification - reproductive toxicity

Argued in:D-76, safety · The safety classification rubric

D-23two ingredients

Level Bposition 2 of 4stated by the source

Metol alone sets the level, and this formula carries nearly four times D-76's dose of it: 7.5 g a litre of an irreversible skin sensitiser, weighed dry. The second consideration is the 100 g/L of sulfite, which is a splash you do not want in an eye rather than a systemic hazard. Nothing in the bath evolves a gas in normal use.

Sources:National Center for Biotechnology Information§ GHS classification - skin sensitisation · National Center for Biotechnology Information§ GHS classification; physical description

Argued in:D-23, safety · The safety classification rubric

D-25minimum grain

Level Bposition 2 of 4stated by the source

D-23's metol dose plus the one ingredient in this column with an incompatibility that matters on a shelf rather than in a tray. Sodium bisulfite is the acid salt of sulfurous acid, and a solution containing it releases sulfur dioxide if it meets a stronger acid; fifteen grams a litre in a mixed developer is not the hazard, the dry jar next to the glacial acetic acid is.

Sources:National Center for Biotechnology Information§ GHS classification - skin sensitisation · National Center for Biotechnology Information§ GHS classification; reaction with acids and the release of sulfur dioxide

Argued in:D-25, safety · Chemical incompatibilities

DK-20thiocyanate

Level Bposition 2 of 4stated by the source

Metol sets the level as everywhere in this column, and the thiocyanate sets the storage rule: strong acid liberates hydrogen cyanide from a thiocyanate. Nothing in normal use goes near that condition, because a stop bath is dilute and the developer is a litre of alkaline solution, but the dry jar is stored away from every acid in the darkroom and the incompatibility page carries the pair.

Sources:National Center for Biotechnology Information§ GHS classification - skin sensitisation · National Center for Biotechnology Information§ GHS classification; the reaction of thiocyanates with strong acid

Argued in:DK-20, safety · Chemical incompatibilities

DK-50brisk, general

Level Bposition 2 of 4stated by the source

The same two agents as D-76 at lower doses - 2.5 g of metol and 2.5 g of hydroquinone a litre - and neither dose changes the classification, because sensitisation is a property of the substance rather than of the concentration and hydroquinone's eye-damage classification applies to the powder being weighed.

Sources:National Center for Biotechnology Information§ GHS classification - skin sensitisation · National Center for Biotechnology Information§ GHS classification - Danger, serious eye damage

Argued in:DK-50, safety · The safety classification rubric

D-19bhigh contrast

Level Bposition 2 of 4stated by the source

The largest hydroquinone dose of the six at 8.8 g a litre, weighed as a powder, plus 48 g of anhydrous sodium carbonate, which is an eye irritant as a dust and the reason the alkali is added under the extraction rather than in a draught. Metol at 2.2 g completes the set.

Sources:National Center for Biotechnology Information§ GHS classification - Danger, serious eye damage, suspected carcinogenicity · Prepared by an international group of experts on behalf of the International Labour Organization and the World Health Organization, with the financial assistance of the European Commission, 2024§ Routes of exposure and inhalation risk; eye and respiratory tract irritation · National Center for Biotechnology Information§ GHS classification - skin sensitisation

Argued in:D-19b, safety

Beutlerhigh acutance

Level Bposition 2 of 4stated by the source

Metol sets it, as it does for D-23, and 10 g of an irreversible skin sensitiser is weighed dry for each litre of stock A. The second consideration is 50 g of sodium carbonate a litre, which is an alkaline dust rather than a systemic hazard and would not on its own take the formula past Level A. What is absent is as much of the classification as what is present: no hydroquinone, no borax, no caustic alkali and no sulfide, so nothing here evolves a gas at any stage and the ventilation requirement is for dust at the balance rather than for vapour at the tray.

Sources:National Center for Biotechnology Information§ GHS classification - skin sensitisation · National Center for Biotechnology Information§ GHS classification - serious eye irritation

Argued in:Beutler, safety · The safety classification rubric

PMKstaining

Level Bposition 2 of 4stated by the source

Pyrogallol alone decides it, and it is the most heavily classified developing agent in this reference: harmful in contact with skin, harmful if inhaled and suspected of causing genetic defects at every notification its encyclopaedia page aggregates, with no workplace exposure limit in EH40 to measure against - which means the control is not to make dust at all. Both makers publish their own warnings and they agree, and Rempel's handbook heads its entry "use with extreme caution". The hazardous operation is weighing 25 g of a dusty phenol once per batch, not the tray: the working bath is under a gram a litre. Sodium metaborate adds a reproductive-toxicity notification and metol the sensitiser one.

Sources:National Center for Biotechnology Information§ GHS classification · Photographers' Formulary Inc.§ FOR YOUR CHEMICAL SAFETY · Siegfried Rempel and Wolfgang Rempel, 1992§ The PYROGALLOL (PYRO) hazard entry, headed Use With Extreme Caution

Argued in:PMK, safety · The safety classification rubric

Rodinal typeWall, 1924

Level Bposition 2 of 4stated by the source

The only formula in this matrix whose level is set by the alkali rather than by the developing agent. Sodium hydroxide is classified Danger for severe skin burns and eye damage, and this formula asks for 215 g of it in 500 mL of water - about 430 g/L, near a saturated solution, dissolved with strong evolution of heat that Kodak's 1928 primer says will make a solution boil with explosive violence if hot water is used. Para-aminophenol supplies the second criterion, harmful if inhaled as a dry powder and a sensitiser by about a third of its notifications. It does not reach Level C: no fume cupboard is the recognised control for any step, and HSE's COSHH essentials sheet for manual film development asks for general ventilation, nitrile gloves and eye protection.

Sources:Eastman Kodak Company, 1928§ The caustic alkalis, and formula D-9 with its warning that the solution will boil with explosive violence · National Center for Biotechnology Information§ GHS classification - harmful if inhaled, suspected of causing genetic defects · Health and Safety Executive, 2022§ Equipment and procedures; Respiratory protective equipment; Gloves; Other equipment

Argued in:Rodinal type, safety · The safety classification rubric

Waste stream

The question Which of the five streams that leave a silver darkroom does the spent bath belong to?

The stream is chemistry and does not change. What may lawfully be done with it depends on where you are, differs between authorities in one country, and changes; the disposal page carries that in full and this column does not repeat it per row.

The scale: Waste route, a set of alternatives with no ordering

Which of the five streams that leave a silver darkroom this bath belongs to. They are kept apart because they are chemically incompatible and have different destinations, and that much is a consequence of reactions rather than of statutes. What may lawfully be done with any of them depends on where you are.

1. Developer streamAlkaline, organic and oxygen-demanding. Its own labelled container, and never mixed with the fixer bottle, which would ruin a recoverable solution.
2. Stop bath streamAcid. Its own container: acid meeting a sulfite or a thiosulfate liberates sulfur dioxide at once.
3. Fixer and silver streamThiosulfate carrying dissolved silver, at thousands of milligrams per litre. It never goes to a drain and it is the stream silver recovery exists for.
4. Hazardous collection onlyA heavy metal, a sulfide or a cyanide bath. The whole volume is a collected waste and no part of it is a drain question.

Where a cell is empty The waste chemistry of the bath has not been established.

D-76the borax standard

Developer streamstated by the source

Spent D-76 is a dilute alkaline solution whose environmental load is the developing agents and the sulfite rather than the borax: both agents carry aquatic-toxicity classifications, and borate is a registered vegetation control, so it does not go on the garden whatever its pH. It carries almost no silver, which is exactly why it must not go in the fixer bottle - that would spoil a solution that would otherwise go for silver recovery.

Sources:Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals; keeping streams separate · National Center for Biotechnology Information§ GHS classification - hazardous to the aquatic environment

Argued in:D-76, waste · The disposal caveat

D-23two ingredients

Developer streamstated by the source

The same stream and the simplest case in it: metol and sulfite, no hydroquinone, no borate. Oxygen demand from 100 g of sulfite a litre is the load rather than any single toxic component, and the bottle is still kept apart from the fixer, because a developer bottle contaminated with thiosulfate is a silver-recovery problem rather than a developer problem.

Sources:Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals; keeping streams separate

Argued in:D-23, waste · The disposal caveat

D-25minimum grain

Developer streamstated by the source

As D-23, with one extra rule that follows from the bisulfite rather than from the developer: nothing acid goes into this bottle. Acid meeting a sulfite or a bisulfite liberates sulfur dioxide at once, in a sealed container, and that is a consequence of the reaction rather than of any regulation.

Sources:Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals · National Center for Biotechnology Information§ Reaction with acids and the release of sulfur dioxide

Argued in:D-25, waste · The disposal caveat

DK-20thiocyanate

Developer streamstated by the source

The developer stream, and the one bath of the six whose waste bottle carries an additional absolute rule: a thiocyanate solution must never be acidified, in a container or in a drain. The stream is otherwise the usual alkaline organic one, and the thiocyanate is the reason this bottle is labelled rather than merely kept.

Sources:Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals · National Center for Biotechnology Information§ GHS classification; the reaction of thiocyanates with strong acid

Argued in:DK-20, waste · Chemical incompatibilities

DK-50brisk, general

Developer streamstated by the source

The developer stream, with the lightest load of the six: a third of D-76's sulfite and half its hydroquinone in the same volume. The borate question does not arise, because the alkali is a metaborate rather than borax - the same element in a different salt, and the course records that the price file and the encyclopaedia treat them as different substances.

Sources:Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals

Argued in:DK-50, waste · The disposal caveat

D-19bhigh contrast

Developer streamstated by the source

The developer stream, and the highest load in this column: the largest hydroquinone dose, 48 g of carbonate a litre making it the most alkaline of the six, and 4 g of bromide. A high-contrast bath used for volume work also produces the most of it, which is a practical point about collection rather than about chemistry.

Sources:Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals · National Center for Biotechnology Information§ GHS classification - hazardous to the aquatic environment

Argued in:D-19b, waste · The disposal caveat

Beutlerhigh acutance

Developer streamstated by the source

The developer stream, with one property worth stating: because the bath is discarded after a single film, a session pours away several times the volume a reusable tank developer would, at about a twelfth of the concentration. The load is the metol and its oxidation products rather than the carbonate or the small sulfite dose, and the bottle is still kept apart from the fixer, because a developer bottle contaminated with thiosulfate stops being a recoverable solution.

Sources:Eastman Kodak Company, 1999§ Table I, General Guidelines, the Developer used and unused rows; keeping streams separate

Argued in:Beutler, waste · The disposal caveat

PMKstaining

Developer streamstated by the source

The developer stream, and the most heavily classified entry in it. Three of the four ingredients carry an environmental classification: pyrogallol is harmful to aquatic life with long-lasting effects, metol very toxic to it with long-lasting effects, and the borate does not degrade. The bath is also alkaline enough to matter on its own account, since even a 0.1 per cent metaborate solution reads about pH 10.5 against sewer windows commonly set around 5.6 to 9.4. It is kept out of the acid stream for a second reason as well: A solution's bisulfite gives sulfur dioxide with acid.

Sources:National Center for Biotechnology Information§ GHS classification - hazardous to the aquatic environment · Photographers' Formulary Inc.§ The disposal line - consult local sewer and water authorities

Argued in:PMK, waste · The disposal caveat

Rodinal typeWall, 1924

Developer streamstated by the source

The developer stream, and the page routes it further than the others in this column: para-aminophenol is very toxic to aquatic life with long-lasting effects in every notification that classifies it, and neutralising the alkali would do nothing about that half of the problem, so the spent bath goes to a licensed hazardous-waste route rather than to a drain. Unused caustic soda solution is a second and separate waste, corrosive rather than aquatically toxic, and is kept and labelled apart from the spent developer.

Sources:National Center for Biotechnology Information§ GHS classification - hazardous to the aquatic environment, long-term · National Center for Biotechnology Information§ GHS classification - skin corrosion

Argued in:Rodinal type, waste · The disposal caveat

Suitability for scanning

The question Does any source in this course's corpus state a contrast aim, a density range or a developer choice for a negative that will be scanned rather than printed?

Empty for all six, for one reason, stated once. This is the axis where a star rating would have been easiest to invent and least defensible.

The scale: Kind of claim, a set of alternatives with no ordering

For an axis where the only honest answer is who says so: a claim published by the maker, or a behaviour this course has measured for itself.

1. Published by the makerThe maker states it in a document this course holds.
2. Measured by the courseThis course measured it, and the page carries the method and the numbers.

Where a cell is empty No document in this course's corpus states a contrast-index band for scanning. Part XIII establishes that directly while setting out the aims that are published: Kodak's own starting points are given for a diffusion enlarger and adjusted for a condenser, ILFORD quantifies the enlarger difference as about a grade, and neither says anything about a scanner. Until the course can cite a scanner aim, every cell in this column is empty. What would settle it is a manufacturer or standards document giving a target for scanning, or the course's own measured comparison once Part XIII's practical work is performed.

D-76the borax standard

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-23two ingredients

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-25minimum grain

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

DK-20thiocyanate

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

DK-50brisk, general

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-19bhigh contrast

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Beutlerhigh acutance

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

PMKstaining

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Rodinal typeWall, 1924

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Materials it is published for

The question Which materials does the maker publish this developer for — negatives only, or prints as well?

The brief's axis is "printing suitability", which can mean either a developer that suits paper or a negative that suits an enlarger. This column answers the first, because it is a statement the sources actually make; the second is the enlarger question, and Part XIII owns it.

The scale: Materials it is published for, a set of alternatives with no ordering

Which materials the maker publishes the formula for. It is a statement about the document, not a judgement about what would happen if you used it elsewhere.

1. Film and platesPublished for negative materials only.
2. Film, plates and paperPublished for negative materials and for prints.
3. PaperPublished for prints only.
4. Paper and hand-coated processesPublished for prints, including hand-coated and printing-out papers.

Where a cell is empty The source does not say what materials the formula is for, which for a manufacturer's own sheet would be remarkable and for a formula printed in a handbook is ordinary.

D-76the borax standard

Film and platesstated by the source

Kodak publishes D-76 for negative materials: films and plates, with development tables for roll and sheet film and nothing for paper. The 1949 handbook lists it among the negative developers and prints separate formulas for prints, which is a statement about what the document covers rather than a prediction about what would happen on a sheet of bromide paper.

Sources:Kodak Alaris Inc., 2017§ Development-time tables at full strength and 1:1 · Kodak Limited, 1949§ Kodak formula D-76; the negative developer tables

Argued in:D-76, recommended uses

D-23two ingredients

Film and platesstated by the source

Published for plates and films, at about eighteen minutes at 18 degrees C, and for nothing else. A bath with no alkali beyond its own sulfite is not a paper developer in any case, since a print developer's job is to reach maximum black quickly and this one is designed to reach it slowly.

Sources:Kodak Limited, 1949§ Kodak formula D-23, with its description and its development time

Argued in:D-23, recommended uses

D-25minimum grain

Film and platesstated by the source

Published for plates and films only. The exposure penalty Kodak attaches to it is a statement about negative material, and the formula's whole purpose - minimum grain - is a property of a negative that will be enlarged rather than of a print.

Sources:Kodak Limited, 1949§ Kodak formula D-25, with its description and its exposure warning

Argued in:D-25, recommended uses

DK-20thiocyanate

Film and platesstated by the source

Published for plates and films, in a dish or a deep tank, with a replenisher for tank working. Kodak's packed-developer list places it among the fine-grain negative developers, and fine grain is a negative property.

Sources:Kodak Limited, 1949§ Kodak formula DK-20; Some Kodak packed developers

Argued in:DK-20, recommended uses

DK-50brisk, general

Film and platesstated by the source

Published for plates and films. It is the general-purpose negative developer of the 1949 handbook - brisk, adjustable through the alkali, with the highest deep-tank capacity on the table - and the handbook prints the D-160 series and D-72 for paper.

Sources:Kodak Limited, 1949§ Kodak formula DK-50, with its dissolving instruction and its development time

Argued in:DK-50, recommended uses

D-19bhigh contrast

Film, plates and paperstated by the source

The only one of the six that Kodak publishes for prints as well as negatives, and the handbook's wording is what makes it so: use without dilution, or diluted as directed in the instructions issued with the material to be developed. A high-contrast developer covering line work on film, plate and paper is doing one job across three materials rather than three jobs.

Sources:Kodak Limited, 1949§ Kodak formula D-19b, its description and its dilution instruction

Argued in:D-19b, recommended uses

Beutlerhigh acutance

Film and platesstated by the source

Windisch's heading is a special developer for low-speed films, and he defines the target as 8 to 16 ASA; Haist files it among high-definition developers for negatives; the annual prints it under acutance formulae. No source in the corpus offers it for paper, and a bath holding 0.83 g of developing agent a litre is not a print developer in any case, since a print developer's job is to reach maximum black quickly.

Sources:Hans Windisch, 1956§ A special developer for low-speed films, and the definition of low-speed film as 8 to 16 ASA · Aaron Sussman, 1965§ The developing chapter's Beutler formula - the instruction to develop slow emulsions for 7 to 10 minutes

Argued in:Beutler, recommended uses

PMKstaining

Film and platesstated by the source

Both makers publish this developer for film and for nothing else: the Formulary's second sheet is four tables of development times for Ilford, Kodak, Agfa and other films, and BERGGER's is a film-processing procedure with a time and temperature chart. Neither offers a paper time, and a bath whose whole product is a stain that acts as a filter over a variable-contrast paper's blue-sensitive layer is aimed at the negative by design.

Sources:Photographers' Formulary Inc.§ DEVELOPMENT TIMES, the Ilford, Kodak, Agfa and Other Films tables · BERGGER, 2020§ Film processing; the Time / Temp Chart

Argued in:PMK, recommended uses

Rodinal typeWall, 1924

Film, plates and paperstated by the source

The only subject in this matrix published for prints as well as negatives, and the source gives exactly two uses and no time for either: plates at 1 part in 10 with potassium bromide added, and papers at 1 part in 40. Wall's 1912 entry for the proprietary developer of the same type recommends it for bromide paper and lantern slides, which is the same answer from the other direction. The register files the entry as a film developer because that is what the class became, and the mismatch with what its source actually says is left standing rather than tidied.

Sources:E. J. Wall, F.C.S., F.R.P.S., 1924§ Developers, pages 108 and 109 - the two dilutions, for plates and for papers · E. J. Wall, edited by F. J. Mortimer, 1912§ Development and Developers - Rodinal, the recommendation for bromide paper and lantern slides

Argued in:Rodinal type, recommended uses

Sheet film

The question Does the maker publish a capacity or a working practice for this developer in sheets rather than only in rolls?

The scale: Does the source say so, a set of alternatives with no ordering

For an axis that asks a plain question of the evidence. Yes and no are both statements a source makes; a source that says nothing produces an unscored cell instead.

1. YesA source states it.
2. Yes, with a conditionA source states it and attaches a condition, which the cell gives.
3. NoA source states the opposite.

Where a cell is empty The maker publishes no capacity figure for the formula in any unit, so there is nothing to say about sheets specifically.

D-76the borax standard

Yesstated by the source

Kodak publishes capacity in sheets in two independent places. J-78 gives 16 sheets of 8 by 10 inches per US gallon unreplenished, with the time raised 15 per cent after every four, and 480 sheets of 4 by 5 or 120 of 8 by 10 replenished with no time increase; the 1949 handbook gives 24 sheets in a dish and 36 in a deep tank per 160 imperial fluid ounces.

Sources:Kodak Alaris Inc., 2017§ Storage life and capacity; replenished capacity · Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:D-76, behaviour

D-23two ingredients

Yesstated by the source

The 1949 capacity table is stated in sheets of 8 by 10 inches throughout, and D-23 takes 24 in a dish and 36 in a deep tank per 160 imperial fluid ounces. The dish figure matters more than the tank one for sheet work, since dish development is how sheets are usually handled by hand.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:D-23, behaviour

D-25minimum grain

Yesstated by the source

20 sheets of 8 by 10 inches in a dish and 30 in a deep tank per 160 imperial fluid ounces - the lowest pair on the 1949 table. Sheet capacity and grain move in opposite directions across this column, and D-25 is at the extreme of both.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:D-25, behaviour

DK-20thiocyanate

Yesstated by the source

24 sheets of 8 by 10 inches in a dish and 36 in a deep tank per 160 imperial fluid ounces, the tank figure carrying the table's footnote that the life is greatly increased by replenishment. DK-20R's own rate is given per thousand rolls rather than per sheet, so the two figures are not directly comparable and the page says so.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions; Kodak formula DK-20R

Argued in:DK-20, behaviour

DK-50brisk, general

Yesstated by the source

24 sheets of 8 by 10 inches in a dish and 48 in a deep tank per 160 imperial fluid ounces, twice the dish figure and the largest gap between the two conditions of any developer here. Two pages of this course disagree about which deep-tank figure is the table's highest: DK-50's page calls its 48 sheets the highest deep-tank figure of any developer on the table, and D-19b's calls its own 72 the highest figure on the whole developer table. Both cannot be right, and the matrix records the disagreement rather than quietly picking one.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:DK-50, behaviour

D-19bhigh contrast

Yesstated by the source

36 sheets of 8 by 10 inches in a dish and 72 in a deep tank per 160 imperial fluid ounces - the dish figure half again the 24 that D-76, D-23, DK-20 and DK-50 all take, and the tank figure double their 36. A bath that develops to high contrast in a short time exhausts less silver per sheet, and the capacity table shows it. Two pages of this course disagree about which deep-tank figure is the table's highest: DK-50's page calls its 48 sheets the highest deep-tank figure of any developer on the table, and D-19b's calls its own 72 the highest figure on the whole developer table. Both cannot be right, and the matrix records the disagreement rather than quietly picking one.

Sources:Kodak Limited, 1949§ Keeping properties and useful life of solutions

Argued in:D-19b, behaviour

Beutlerhigh acutance

Not established

No source publishes a capacity for this developer in any unit, and its constituents are too dilute for one to be worth guessing. That absence matters more here than for a formula worked at stock strength: a tray of this bath standing between sheets is a different bath by the third sheet, so a sheet-film worker needs the figure that does not exist rather than merely being denied a convenience.

Sources:Grant Haist, 1979§ High-definition developers - the Beutler formula printed as two solutions of a litre each, with no capacity

Argued in:Beutler, behaviour

PMKstaining

Yesstated by the source

Both makers state their minimum-volume rules in sheets as well as rolls - the Formulary's 300 mL per 80 square inches is glossed as four 4 by 5 sheets, and BERGGER's litre per 1,000 square centimetres as two 8 by 10 sheets or eight 4 by 5 - and the formula came out of large-format practice, which is why its published flexibility for plus and minus development is a sheet-film idea. This is the only subject in the column whose sheet answer comes from a minimum rather than from a capacity.

Sources:Photographers' Formulary Inc.§ CAPACITY OF PMK · BERGGER, 2020§ Use - capacity, listed as two 8x10 sheets, eight 4x5 sheets or two 135-36 rolls

Argued in:PMK, behaviour

Rodinal typeWall, 1924

Yes, with a conditionstated by the source

Wall publishes a working practice for individual sheets before he publishes one for anything else: plates at 1 part in 10, which is the strongest dilution he gives. The condition is what he leaves out - potassium bromide is to be added and he does not say how much, and he gives no development time for the plate dilution at all, so the practice is stated and cannot be followed as printed. Foma's capacity for its own product, up to 62 sheets of 13 by 18 cm from 250 mL, belongs to a different developer.

Sources:E. J. Wall, F.C.S., F.R.P.S., 1924§ Developers, page 109 - plates at 1 in 10 with potassium bromide added

Argued in:Rodinal type, recommended uses

Push processing

The question Does the maker publish extended development for underexposed film in this developer, and say what it costs in fog?

The scale: Does the source say so, a set of alternatives with no ordering

For an axis that asks a plain question of the evidence. Yes and no are both statements a source makes; a source that says nothing produces an unscored cell instead.

1. YesA source states it.
2. Yes, with a conditionA source states it and attaches a condition, which the cell gives.
3. NoA source states the opposite.

Where a cell is empty The maker publishes no push-processing instruction for this formula. Extended development is possible in any developer; what is missing is a published time, a published fog consequence and a published limit, and without those the course has nothing to state. What would settle it is a manufacturer time table for pushed film in this bath.

D-76the borax standard

Yes, with a conditionstated by the source

The claim is published and the times are not. Kodak's own description of D-76 is a developer with enough development latitude to push at relatively low fog, which is the only push statement attached to any of these six formulas anywhere in the corpus. What the course does not hold is a time table for a pushed film in it, so the condition on this score is that you have the claim and have to find the time yourself.

Sources:Kodak Alaris Inc., 2017§ The opening description; development-time tables at full strength and 1:1

Argued in:D-76, image characteristics

D-23two ingredients

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-25minimum grain

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

DK-20thiocyanate

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

DK-50brisk, general

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-19bhigh contrast

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Beutlerhigh acutance

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

PMKstaining

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Rodinal typeWall, 1924

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Negatives for hand-coated processes

The question Does any source state a development aim in this developer for a negative destined for a salted paper, cyanotype, kallitype, Van Dyke or palladium print?

The brief asks for this axis and the course cannot yet answer it for any developer. The gap is named rather than filled, and the part that will close it is named with it.

The scale: Does the source say so, a set of alternatives with no ordering

For an axis that asks a plain question of the evidence. Yes and no are both statements a source makes; a source that says nothing produces an unscored cell instead.

1. YesA source states it.
2. Yes, with a conditionA source states it and attaches a condition, which the cell gives.
3. NoA source states the opposite.

Where a cell is empty Nothing in this course's corpus ties one of these developers to a hand-coated printing process. What the process atlas establishes is the demand: those processes are self-masking and want a negative of long density range, and one made for enlarging paper prints flat on them. What is still missing is a number. Parts XXI and XXV are now written and both state the demand in words; neither publishes a density range, a contrast index or a development time in a named developer for a negative destined for a hand-coated print, and the one-negative-in-seven-processes comparison that would produce one is an assignment nobody has yet returned. Until a student does, or a source states one, the honest cell is empty.

D-76the borax standard

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-23two ingredients

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-25minimum grain

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

DK-20thiocyanate

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

DK-50brisk, general

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

D-19bhigh contrast

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Beutlerhigh acutance

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

PMKstaining

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.

Rodinal typeWall, 1924

Not established

Nothing specific to this subject to add: the column’s own note above is the whole answer.