Toners compared

The most useful thing this matrix does is put the first column first. Three of these seven baths turn the image into silver sulfide, three deposit gold on it, and one is a selenium compound the course could not identify with confidence. Once that is on the page, the rest of the row follows: the colour, the density change, the permanence claim and the hazard are all consequences of which of those three things the bath does.

!A blue toner and a warm-brown toner, with the same chemistry

T-21 gives brown tones and T-26 gives blue, and both are gold baths working through the same reduction of gold(III) to gold(I) with a different sulfur ligand. They also tone in opposite orders — T-21 uniformly across the scale, T-26 highlights first — and ask for opposite exposure corrections. Two baths that need the print to be made differently before they are reached are not interchangeable, whatever they have in common, and a star rating would have hidden every part of that.

Toners

Seven after-treatments for a developed-out silver print - three routes to sulfide, three to gold and one to selenium - compared on what they do to the silver, to the colour, to the density and to the permanence.

7 subjects on 11 axes. 64 of the 77 cells carry a score with its reasoning and its source; 13 are not established, of which 1 say why for that subject in particular and 12 are answered by their column's own note.

What is in this matrix, and what is not

Toners for a developed-out silver gelatin print, which is a narrower set than the formulary holds and a coherent one: every bath here is applied to a finished, fixed, washed print, and any of them could be used on the same print, so they are genuine alternatives. The gold and platinum baths for printing-out papers are not in this matrix, because in printing-out practice the toning bath comes before the fixer and is part of making the image rather than an after-treatment of it; they belong with their processes. The iron-blue toner the brief names has no formula in this reference, and its absence is a gap rather than a decision. Two of these seven are Level D or restricted, and the matrix marks them rather than quietly dropping them.

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

Axis	T-7asulfide sepia	T-52sulphide, 1949	T-1ahypo alum sepia	T-21gold, warm brown	T-26gold, blue	GP-1gold protective	T-55selenium, Level D
What the silver becomes	Silver sulfide	Silver sulfide	Silver sulfide	Gold on the silver	Gold on the silver	Gold on the silver	—not established
Colour	Warm brown to sepia	Warm brown to sepia	Cold brown to chocolate	Set by the paper	Blue	Little change	Set by the paper
Density and contrast	Lowered1/3	Lowered1/3	Lowered1/3	—not established	Raised3/3	Unchanged2/3	Raised3/3
Where it starts	Highlights first	—not established	Highlights first	Uniformly	Highlights first	—not established	—not established
Protects the image	Yes	Yes	—not established	Yes	Yes, with a condition	Yes	Yes
One-shot or reusable	One-shot	One-shot	Reusable	Replenished	One-shot	One-shot	Reusable
Materials it is published for	Film, plates and paper	Paper	Paper	Paper	Paper	Paper	Paper
Complexity	Involved3/4	Involved3/4	Involved3/4	Involved3/4	Moderate2/4	Simple1/4	Specialist4/4
Safety classification	Level C3/4	Level C3/4	Level B2/4	Level C3/4	Level C3/4	Level B2/4	Level D4/4
Waste stream	Hazardous collection only	Hazardous collection only	Fixer and silver stream	Hazardous collection only	Hazardous collection only	Hazardous collection only	Hazardous collection only
Cost	—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. 1 of the 11 axes are empty for every subject (Cost), and each of them says why in its own section.

What the silver becomes

The question What does this bath convert the image silver into, and does a source establish it?

The scale: What the silver becomes, a set of alternatives with no ordering

The chemical change the toner makes to the image. It decides the colour, the permanence claim and the hazard together, so it is the first column of the toner matrix for the same reason the kind of bath is the first column of the fixer matrix.

1. Silver sulfideThe image silver is converted to silver sulfide, directly or by bleaching to a halide and redeveloping in a sulfide bath.
2. Gold on the silverGold(I) is reduced onto the image particles, one gold atom for one silver, coating them in a metal that does not tarnish.
3. A selenium compoundSelenium enters the image. Which compound results is a question the course records rather than settles.

Where a cell is empty The course could not establish what the image substance becomes.

T-7asulfide sepia

Silver sulfidestated by the source

An indirect sulfide toner: the ferricyanide-bromide bleach oxidises the metallic silver and the bromide catches it as silver bromide, then the sulfide bath exchanges the halide for a sulfide. The metathesis is driven by solubility - silver bromide's solubility product is about 5 x 10 to the minus 13 and silver sulfide's about 1.6 x 10 to the minus 49 - so the reaction has nowhere else to go.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Sulfide Sepia Toner T-7a, page 7

Argued in:T-7a, the mechanism · The two conversions, in full

T-52sulphide, 1949

Silver sulfidestated by the source

The same two conversions with a wash between them, and the wash is there because the two chemistries must not meet. This is the page that carries the equations for the whole sulfide family in this reference, and T-7a's page points at it rather than repeating them.

Sources:Kodak Limited, 1949§ Kodak formula T-52, page 39, metric column

Argued in:T-52, the mechanism

T-1ahypo alum sepia

Silver sulfidestated by the source

The same end product by a route that makes its own sulfur in the tray. Alum in water is weakly acid, acid added to hypo precipitates sulfur, and there is no sulfite here to defend the thiosulfate - which is the difference between this bath and every fixing bath in the formulary. Hot, and in one bath rather than two.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Hypo Alum Sepia Toner T-1a, page 6 · Eastman Kodak Company, 1928§ The behaviour of acid with hypo and the precipitation of sulfur

Argued in:T-1a, the mechanism

T-21gold, warm brown

Gold on the silverstated by the source

The whole formula is an apparatus for reducing gold(III) to gold(I), because a plain gold(III) bath spends three silver atoms for every gold atom deposited and bleaches the print faster than it tones it. T-21 does it with a thiosulfate bath, a persulfate and a silver-chloride charge added to the stock.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Toner T-21, pages 7 and 8

Argued in:T-21, the mechanism · Chloroauric acid, and the three-for-one problem

T-26gold, blue

Gold on the silverstated by the source

A third sulfur ligand and the same reduction as the other two gold toners: thiourea takes gold(III) to gold(I), where the exchange with silver is one for one. That a blue toner and a warm-brown toner are the same chemistry with a different ligand is the most surprising thing in this matrix and the best argument for reading the first column before the second.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Blue Toner T-26, page 8

Argued in:T-26, the mechanism

GP-1gold protective

Gold on the silverstated by the source

A reduction run in a beaker in the two minutes before the print goes in: the thiocyanate goes into the gold rather than the other way round, and the gold(I) that results coats the image particles. Kodak's whole description of the visible effect is changing the image tone only slightly, which is what a one-for-one exchange with no bleaching looks like.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Protective Solution GP-1, page 8

Argued in:GP-1, the mechanism

T-55selenium, Level D

Not established

The course records what it could not settle. Kodak Limited's preparation is to dissolve sodium sulfite, add selenium powder and boil until dissolved, and the wider chemical literature calls that product a selenosulfate; what the modern packaged selenium toners contain is described by their maker only as a sulfite salt, and the course will not close the gap between the two. A toner whose active compound is an open question cannot have that compound scored here.

Sources:Kodak Limited, 1949§ Kodak formula T-55, page 40, metric column and its preparation

Argued in:T-55, the mechanism and what is contested in it · Sodium selenosulfate, and the open question

Colour

The question What colour does the maker publish for this bath, and what does the maker tie the exact hue to?

The scale: Colour it gives, a set of alternatives with no ordering

What the toner does to the colour of the print. In every one of these baths the hue is inherited from the image that went in as much as from the bath, so the cell says what the source ties it to.

1. Warm brown to sepiaThe classic sepia range, running from light brown to nearly black with the state of subdivision of the sulfide.
2. Cold brown to chocolateA colder brown, and the source ties the exact hue to the colour of the untoned print.
3. BlueBlue on some papers, and the source is careful about which.
4. Little changeThe bath is used for what it does to the image's stability rather than for a colour shift.
5. Set by the paperThe source names the papers rather than the hue, because the result is a property of the emulsion.

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

T-7asulfide sepia

Warm brown to sepiastated by the source

Warm-brown tones, which Kodak's own sheet describes as similar to those of its packaged Sepia Toner. The exact hue follows the paper and the original image rather than the bath, which is the rule for the whole sulfide family and the reason two prints from the same bath can differ.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Sulfide Sepia Toner T-7a, page 7

Argued in:T-7a, image characteristics

T-52sulphide, 1949

Warm brown to sepiastated by the source

Warm brown to sepia, and the 1928 primer is precise about why the range exists: silver sulfide runs from light brown to black according to its state of subdivision, and the subdivision is inherited from the image that was bleached. The bath does not choose the colour; the print that goes in does.

Sources:Kodak Limited, 1949§ Kodak formula T-52, page 39 · Eastman Kodak Company, 1928§ Sulphide toning and the colour of silver sulfide according to its state of subdivision

Argued in:T-52, image characteristics

T-1ahypo alum sepia

Cold brown to chocolatestated by the source

Cold brown to chocolate, and the 1928 primer ties it directly to the print that went in: blue-black images give cold chocolate tones and olive green images give warm sepia. It is the colder end of the sepia range and the reason a printer chooses it over a bleach-and-redevelop bath.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Hypo Alum Sepia Toner T-1a, page 6 · Eastman Kodak Company, 1928§ Sulphide toning, on blue-black images giving cold chocolate tones and olive green images warm sepia

Argued in:T-1a, image characteristics

T-21gold, warm brown

Set by the paperstated by the source

A range of brown tones on most warm-tone papers and little effect on cold-tone ones. Kodak names the paper class rather than the hue, which is the honest form for a gold bath whose result depends on the size of the silver particles it is coating.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Toner T-21, pages 7 and 8

Argued in:T-21, image characteristics

T-26gold, blue

Bluestated by the source

Blue on some papers, and Kodak is careful about which: warm-tone papers react well, neutral-tone papers change slightly to a soft blue-black, and cold-tone papers will not change at all. Kodak adds that a soft grey-blue is more common than a saturated blue, which is the sort of qualification a matrix exists to preserve.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Blue Toner T-26, page 8

Argued in:T-26, image characteristics

GP-1gold protective

Little changestated by the source

Kodak's whole description of the effect is changing the image tone only slightly, and the end point is a very slight change to a bluish black. A bath whose colour effect is almost nothing is not a failed toner: it is a protective bath, and the next column is the one it is judged on.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Protective Solution GP-1, page 8

Argued in:GP-1, image characteristics

T-55selenium, Level D

Set by the paperstated by the source

Kodak Limited names the papers rather than the colour - Bromesko and warm-tone lantern slides - and the modern sheets are explicit that the effect ranges from a cool chocolate-brown on warm-tone papers to no visible change at all on cold-tone ones. What a selenium toner does to colour is a property of the paper.

Sources:Kodak Limited, 1949§ Kodak formula T-55, page 40 · HARMAN technology Limited (ILFORD Photo)§ The range of effects from warm-tone to cold-tone papers

Argued in:T-55, image characteristics

Density and contrast

The question What does the maker say the bath does to density and contrast, and what compensation does it publish?

The scale: Effect on density and contrast, ordered

What the toner does to the print's density, and what the maker publishes as the compensation. It is the axis a printer has to act on before making the print, not after.

1. 1LoweredDensity and contrast fall, and the maker's compensation is more exposure and more development at the enlarger.
2. 2UnchangedThe maker publishes no density change, which for a protective bath is the point.
3. 3RaisedDensity or apparent contrast rises, and the maker's compensation is to reduce the print exposure.

Where a cell is empty The maker publishes no density or contrast effect, and the course will not deduce one from the chemistry: an incomplete conversion loses density and a complete one need not.

T-7asulfide sepia

Loweredposition 1 of 3stated by the source

Slightly reduced, with the density loss that follows any bleach-and-redevelop toner: the conversion is never quite complete, and what is not converted is not there any more either. The compensation is made at the enlarger before the print is toned, not afterwards.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Sulfide Sepia Toner T-7a, page 7

Argued in:T-7a, image characteristics

T-52sulphide, 1949

Loweredposition 1 of 3stated by the source

Slightly lowered in practice through the same incomplete conversion, and Kodak's own advice for its packaged sepia toners is to print slightly darker than normal. The gradation survives the bleach; it is the density that does not.

Sources:Kodak Limited, 1949§ Kodak formula T-52, page 39 · Eastman Kodak Company, 2006§ The instruction to print slightly darker than normal for sepia toning

Argued in:T-52, image characteristics

T-1ahypo alum sepia

Loweredposition 1 of 3stated by the source

Lowered, along with density, and Kodak's answer is more exposure and more development at the enlarger. It is the clearest published compensation of the three sepia routes, and it has to be applied to the negative print before the toning session rather than discovered during it.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Hypo Alum Sepia Toner T-1a, page 6

Argued in:T-1a, image characteristics

T-21gold, warm brown

Not established

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

T-26gold, blue

Raisedposition 3 of 3stated by the source

Appears to increase, along with density, and Kodak's compensation is to reduce the print exposure slightly - the opposite of the advice for every sepia toner in this matrix. Two baths that ask for opposite exposure corrections are not interchangeable, whatever else they have in common.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Blue Toner T-26, page 8

Argued in:T-26, image characteristics

GP-1gold protective

Unchangedposition 2 of 3stated by the source

Kodak publishes no density change and describes the tone change as very slight. For a bath used for protection rather than for colour, an unchanged print is the specification being met and not a disappointment.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Protective Solution GP-1, page 8

Argued in:GP-1, image characteristics

T-55selenium, Level D

Raisedposition 3 of 3stated by the source

Selenium tends to intensify rather than weaken an image, which is the opposite of every sepia toner in this formulary. The direction is what the course states; no figure for the increase is published in the corpus, and none is given here.

Sources:Kodak Limited, 1949§ Kodak formula T-55, page 40 · HARMAN technology Limited (ILFORD Photo)§ The effect on image density and tone

Argued in:T-55, image characteristics

Where it starts

The question Does the maker publish which end of the tonal scale tones first?

The scale: Where it starts, a set of alternatives with no ordering

Which end of the scale tones first. It decides whether a print can be pulled part-way for a chosen hue or whether partial toning gives a split-toned print, and the makers publish it because it changes how the bath is used.

1. Highlights firstThe lightest tones change first and the shadows last, so a partly toned print is split.
2. Shadows firstThe heaviest deposits change first.
3. UniformlyHighlights and shadows tone at the same rate, so the print can be pulled at whatever hue it has reached.

Where a cell is empty The maker does not publish where toning starts. It is a practical detail rather than a chemical one, and only some sheets carry it.

T-7asulfide sepia

Highlights firststated by the source

The highlights carry the least silver and are the first place a tired sulfide stock or an incomplete fix shows itself. Kodak does not publish this as a toning rate, and the course states it as what fails first rather than as what changes first.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Sulfide Sepia Toner T-7a, page 7

Argued in:T-7a, troubleshooting

T-52sulphide, 1949

Not established

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

T-1ahypo alum sepia

Highlights firststated by the source

A fresh, unripened bath attacks the highlights first, which is the whole reason a silver charge - silver nitrate and sodium chloride - is in the formula. The 1928 primer's practical corollary is that a bath which has been somewhat used works better than a fresh one.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Hypo Alum Sepia Toner T-1a, page 6, and the silver ripener · Eastman Kodak Company, 1928§ Hypo alum toning, on a used bath working better than a fresh one

Argued in:T-1a, behaviour

T-21gold, warm brown

Uniformlystated by the source

Kodak's distinguishing claim for T-21 is that it tones the highlights and the shadows at a uniform rate, so the print can be pulled at whatever hue it has reached rather than at a point where one end of the scale has run ahead of the other. It is the only bath in this matrix that offers the hue as a continuous choice.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Toner T-21, pages 7 and 8

Argued in:T-21, behaviour

T-26gold, blue

Highlights firststated by the source

Toning occurs in the highlights first and the shadows last, so a partially toned print has blue highlights against untoned shadows - the exact opposite of T-21's uniform rate, in a bath of the same gold chemistry. Kodak publishes the difference because it changes what a printer can do with a timer.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Blue Toner T-26, page 8

Argued in:T-26, behaviour

GP-1gold protective

Not established

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

T-55selenium, Level D

Not established

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

Protects the image

The question Does the source claim that the bath makes the image more stable, as distinct from changing its colour?

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 No source in the corpus makes a permanence claim for this bath.

T-7asulfide sepia

Yesstated by the source

Silver sulfide is the more inert compound Kodak's general claim is about, and sepia toning is where that claim is strongest. The protection is conditional on the conversion being complete, which is the same condition that decides the density loss, so the two columns are the same fact seen twice.

Sources:Eastman Kodak Company, 2006§ Why tone a print; Sulfide Sepia Toner T-7a, page 7

Argued in:T-7a, behaviour · Sepia toning and permanence

T-52sulphide, 1949

Yesstated by the source

The same conversion and the same claim. What the course adds is the condition the process page carries: an incompletely converted print holds both silver and silver sulfide, and the untoned remainder is no better protected than it was before the print went into the bleach.

Sources:Eastman Kodak Company, 2006§ Why tone a print - toning converts the silver image to a more inert compound · Kodak Limited, 1949§ Kodak formula T-52, page 39

Argued in:Sepia toning and permanence

T-1ahypo alum sepia

Not established

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

T-21gold, warm brown

Yesstated by the source

Gold coats the image particles with a metal that does not tarnish, which is the mechanism behind Kodak's general claim in this publication. T-21 gets its protection as a by-product of a bath chosen for its colour, which is the difference between it and GP-1 rather than a difference in the chemistry.

Sources:Eastman Kodak Company, 2006§ Why tone a print; Gold Toner T-21, pages 7 and 8

Argued in:T-21, behaviour · Gold toning and permanence

T-26gold, blue

Yes, with a conditionstated by the source

The gold half of the bath brings the same protection as the other two gold toners. The qualification is the course's own and is on the process page: ILFORD warns that metal replacement toners can reduce image stability, and a blue-toned print is not simply a gold-toned print with a colour change. The claim is therefore made with the warning attached rather than in full.

Sources:Eastman Kodak Company, 2006§ Why tone a print; Blue Toner T-26, page 8

Argued in:Blue toning and image stability

GP-1gold protective

Yesstated by the source

This is the bath's only purpose and its name says so. Kodak's general statement in the same publication is that toning converts the silver image to a more inert compound and that all the toners protect the image whether or not they produce a colour shift; GP-1 is the case where the protection arrives with almost no colour shift at all.

Sources:Eastman Kodak Company, 2006§ Why tone a print - toning converts the silver image to an inert compound and all the toners protect the image whether or not they produce a colour shift; Gold Protective Solution GP-1, page 8

Argued in:GP-1, purpose

T-55selenium, Level D

Yesstated by the source

An observed increase in chemical and environmental stability is what the modern sheets claim for selenium and what the conservation literature reports, and Kodak's general statement in G-23 covers it. The course teaches the claim and not the procedure: the formula is Level D and this page gives no steps.

Sources:HARMAN technology Limited (ILFORD Photo)§ The claim for increased image stability · Eastman Kodak Company, 2006§ Why tone a print - toning converts the silver image to a more inert compound

Argued in:Selenium toning and permanence · The Level D policy

One-shot or reusable

The question How does the source publish the bath being worked?

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 source publishes no working practice for the bath.

T-7asulfide sepia

One-shotstated by the source

A bleach-and-redevelop toner works in baths that are used and discarded: the bleach is spent by the silver it oxidises and the sulfide stock is diluted for use. Kodak publishes no capacity for either half.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Sulfide Sepia Toner T-7a, page 7

Argued in:T-7a, behaviour

T-52sulphide, 1949

One-shotstated by the source

The handbook says the working Toning Solution C is discarded after use. The stocks keep; the bath drawn from them does not, which is the standard shape for a two-solution toner and the reason its keeping row and its reuse row say different things.

Sources:Kodak Limited, 1949§ Kodak formula T-52, page 39, and the instruction to discard the working solution after use

Argued in:T-52, storage

T-1ahypo alum sepia

Reusablestated by the source

The 1928 primer says the bath lasts a long time and that one which has been somewhat used works better than a fresh one, because use supplies the silver a fresh bath takes out of the highlights. It is the only toner in this matrix that improves with age.

Sources:Eastman Kodak Company, 1928§ Hypo alum toning, on the life of the bath and a used bath working better than a fresh one

Argued in:T-1a, behaviour

T-21gold, warm brown

Replenishedstated by the source

Kodak publishes a replenishment rate: 4 mL of Stock Solution B after every fifty 8 by 10 inch prints or the equivalent, when toning to a warm-brown hue. A published rate tied to a stated hue is the strongest working instruction any toner in this matrix carries.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Toner T-21, replenishment

Argued in:T-21, behaviour

T-26gold, blue

One-shotstated by the source

Kodak's instruction is to prepare the solution right before use, and its capacity note is a warning rather than a figure: the first few prints tone the most and the last few may not tone at all, so up to five prints are immersed simultaneously for consistent results.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Blue Toner T-26, page 8, and its capacity and preparation notes

Argued in:T-26, behaviour

GP-1gold protective

One-shotstated by the source

For best results, mix it right before you use it. The formula is a reduction run in a beaker in the two minutes before the print goes in, so the bath has no life to speak of and Kodak does not offer one.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Protective Solution GP-1, page 8

Argued in:GP-1, storage

T-55selenium, Level D

Reusablestated by the source

The 1949 handbook works T-55 as a reusable bath. The course records the practice as history rather than as instruction: the formula is Level D and the page gives its chemistry, its history and its hazards and no procedure.

Sources:Kodak Limited, 1949§ Kodak formula T-55, page 40

Argued in:T-55, behaviour · The Level D policy

Materials it is published for

The question Which materials does the source publish this bath for?

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 the bath is for.

T-7asulfide sepia

Film, plates and paperstated by the source

Published for papers, films and plates. A bleach-and-redevelop toner acts on developed silver wherever it is, and that is what makes this the widest-scope toner in the matrix, though the reason to tone a negative is not the reason to tone a print.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Sulfide Sepia Toner T-7a, page 7

Argued in:T-7a, recommended uses

T-52sulphide, 1949

Paperstated by the source

Kodak Limited publishes T-52 for papers and lantern plates. The course records the plate use with it, because a lantern slide is a plate that is looked through rather than at, and the toning question for it is a different one.

Sources:Kodak Limited, 1949§ Kodak formula T-52, page 39, and the materials it names

Argued in:T-52, recommended uses

T-1ahypo alum sepia

Paperstated by the source

Papers. A hot bath at the temperatures this one runs at is not something to put a negative through, and Kodak does not offer it for one.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Hypo Alum Sepia Toner T-1a, page 6

Argued in:T-1a, recommended uses

T-21gold, warm brown

Paperstated by the source

Papers, and Kodak narrows it further within them: a range of brown tones on most warm-tone papers, little effect on cold-tone ones. The material statement and the colour statement are the same sentence in the source.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Toner T-21, pages 7 and 8

Argued in:T-21, recommended uses

T-26gold, blue

Paperstated by the source

Papers, with the same qualification carried further than any other entry here: warm-tone papers react well, neutral-tone papers change slightly, and cold-tone papers will not change. A material list that includes papers this bath does nothing to is worth reading with the colour column open beside it.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Blue Toner T-26, page 8

Argued in:T-26, recommended uses

GP-1gold protective

Paperstated by the source

Papers. The bath is an archival treatment for a finished print, and Kodak publishes it in the section of G-23 that deals with what toning is for rather than with what it looks like.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Protective Solution GP-1, page 8

Argued in:GP-1, recommended uses

T-55selenium, Level D

Paperstated by the source

Kodak Limited names Bromesko papers and warm-tone lantern slides rather than a material class, which is the same naming habit as T-52 on the facing page and reflects a period catalogue rather than a general rule.

Sources:Kodak Limited, 1949§ Kodak formula T-55, page 40, and the materials it names

Argued in:T-55, recommended uses

Complexity

The question What does making and working this bath demand: how many solutions, in what order, at what temperature, and how long before it can be used?

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 or working instruction.

T-7asulfide sepia

Involvedposition 3 of 4stated by the source

Two baths and a wash between them, and the wash is not a rinse but a requirement: the two chemistries must not meet. The bleach carries four ingredients rather than two, and the extra pair answer two named defects - potassium oxalate, because the blue iron salt that a chipped tray or a steel clip precipitates is soluble in it, and acetic acid, which the 1928 primer adds to prevent blisters.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Sulfide Sepia Toner T-7a, page 7

Argued in:T-7a, mixing

T-52sulphide, 1949

Involvedposition 3 of 4stated by the source

Three published solutions, one of which is drawn from another: Solution C is 50 mL of Stock Solution B made to 1000 mL, which is a solution of the formula rather than a dilution ratio. The print goes through the bleach, a wash and the sulfide bath in turn, and the working bath is discarded afterwards.

Sources:Kodak Limited, 1949§ Kodak formula T-52, page 39, its three solutions and their combination

Argued in:T-52, mixing

T-1ahypo alum sepia

Involvedposition 3 of 4stated by the source

One bath rather than two, which sounds simpler and is not: it is worked hot, it is made from three separate solutions - 480 g of hypo in 2.8 L of water, 120 g of potassium alum in 640 mL, and a silver charge of 4 g of silver nitrate and 4 g of sodium chloride in 64 mL - and the alum solution goes into the hypo before the charge does. A hot tray of sulfurising hypo is a ventilation question as well as a timing one.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Hypo Alum Sepia Toner T-1a, page 6, its solutions and the silver ripener

Argued in:T-1a, mixing

T-21gold, warm brown

Involvedposition 3 of 4stated by the source

Three stocks - a thiosulfate and persulfate bath, a silver chloride charge made in it from silver nitrate and sodium chloride, and the gold - combined in a stated order, plus a replenishment rate to keep track of. It is the most elaborate toner in this reference and the one whose result is most controllable.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Toner T-21, pages 7 and 8, its stock solutions and their order

Argued in:T-21, mixing

T-26gold, blue

Moderateposition 2 of 4stated by the source

One bath from four ingredients, prepared immediately before use, with the gold measured as a volume of stock solution rather than weighed. The care goes into the working rather than the mixing: up to five prints at once, because the bath weakens print by print.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Blue Toner T-26, page 8, and its preparation note

Argued in:T-26, mixing

GP-1gold protective

Simpleposition 1 of 4stated by the source

Two measured volumes, in one order that matters: the thiocyanate goes into the gold and not the other way round. Mixed right before use, in a beaker, in about two minutes. It is the simplest bath in this matrix and the one with the least room to improvise.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Gold Protective Solution GP-1, page 8

Argued in:GP-1, mixing

T-55selenium, Level D

Specialistposition 4 of 4stated by the source

The preparation is to dissolve sodium sulfite, add selenium powder and boil until it dissolves. Boiling elemental selenium in an open vessel is not a domestic operation, and it is the step that puts the formula at Level D rather than anything about using the finished bath.

Sources:Kodak Limited, 1949§ Kodak formula T-55, page 40, and its preparation

Argued in:T-55, and why the course does not give a procedure · The Level D policy

Safety classification

The question What is the course's hazard-assessed level for this bath, 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 bath 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 about the evidence.

T-7asulfide sepia

Level Cposition 3 of 4stated by the source

The formula is Level C because making it is: sodium sulfide is a Level C solid, and sulfide meeting an acid gives hydrogen sulfide in a room that is full of acid. The course's ruling of 5 September 2026 is that the operation sets the level and not the substance, so a lesson that makes the sulfide stock once, outside the session, and doses a dilute working bath inside it runs at Level B on a Level C formula - and says so.

Sources: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, 2002§ Chemical dangers, the reaction with acids · National Center for Biotechnology Information§ GHS classification; the liberation of hydrogen sulfide on contact with acid

Argued in:T-7a, safety · Chemical incompatibilities · The safety classification rubric

T-52sulphide, 1949

Level Cposition 3 of 4stated by the source

The same two chemistries as T-7a and the same classification for the same reason: a ferricyanide bleach that must never meet a strong acid, and a sulfide bath made from a Level C solid. What the level does not mean is that a sepia print cannot be made at Level B - the 5 September 2026 ruling routes around the weighing rather than disputing the classification.

Sources: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, 2002§ Chemical dangers, the reaction with acids · National Center for Biotechnology Information§ GHS classification; the liberation of hydrogen sulfide on contact with acid

Argued in:T-52, safety · Chemical incompatibilities · The safety classification rubric

T-1ahypo alum sepia

Level Bposition 2 of 4stated by the source

No sulfide is added to this bath, which is what separates it from the two bleach-and-redevelop routes: the sulfur is made in the tray from hypo and a weak acid. What is left is a hot concentrated solution and a slow evolution of sulfur dioxide, which is a ventilation control rather than a restricted procedure.

Sources:Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Hypo Alum Sepia Toner T-1a, page 6 · Eastman Kodak Company, 1928§ The behaviour of acid with hypo and the precipitation of sulfur

Argued in:T-1a, safety

T-21gold, warm brown

Level Cposition 3 of 4stated by the source

Potassium persulfate is the substance that sets the level here rather than the gold: it is a strong oxidiser and a sensitiser, and 120 g of it goes into Stock Solution A alongside 960 g of hypo in 4 L of water. The silver nitrate in the charge solution is the second control, and the gold is the least hazardous expensive thing in the formula.

Sources: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§ Chemical dangers as a strong oxidant; routes of exposure and sensitisation · National Center for Biotechnology Information§ GHS classification

Argued in:T-21, safety

T-26gold, blue

Level Cposition 3 of 4stated by the source

Thiourea is what sets the level: it is classified as a suspected carcinogen and for reproductive toxicity, and a gram of it goes into a bath of roughly a litre. The course teaches the formula and marks it, rather than printing a blue toner as though the ligand were incidental.

Sources:National Center for Biotechnology Information§ GHS classification - suspected carcinogenicity and reproductive toxicity

Argued in:T-26, safety

GP-1gold protective

Level Bposition 2 of 4stated by the source

The mildest of the seven. Two measured volumes of stock solutions, no oxidiser, no sulfide and no bleach, and the thiocyanate carries the standing rule that it is never acidified. The level is set by that storage rule rather than by the bath itself.

Sources: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§ Chemical dangers, the reaction with acids

Argued in:GP-1, safety · Chemical incompatibilities

T-55selenium, Level D

Level Dposition 4 of 4stated by the source

Level D: the course gives the chemistry, the history and the hazards and no procedure. Selenium compounds are toxic and cumulative, and the preparation requires boiling elemental selenium powder in an open vessel of sulfite solution. The modern packaged toners exist and are a different question; this formula is studied and not performed.

Sources: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, 1998§ Toxicity and the effects of long-term or repeated exposure to selenium compounds · Kodak Limited, 1949§ Kodak formula T-55, page 40, and its preparation

Argued in:T-55, safety · The Level D policy

Waste stream

The question Which stream does the spent bath belong to, and what is in it?

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.

T-7asulfide sepia

Hazardous collection onlystated by the source

Two streams that are both collected and neither of which is a drain question: a spent ferricyanide bleach carrying the silver it oxidised, and a sulfide bath. Neither meets an acid at any point in its handling, which is the rule that governs the labelling of both containers.

Sources:Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals · 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, 2002§ Chemical dangers; environmental data

Argued in:T-7a, waste · The disposal caveat

T-52sulphide, 1949

Hazardous collection onlystated by the source

The same two collected streams as T-7a. The bleach carries the image silver as a halide and then as a complex, and the sulfide bath is collected whole; the course's disposal page classes the pair with the streams that never reach a drain.

Sources:Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals · 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, 2002§ Chemical dangers; environmental data

Argued in:T-52, waste · The disposal caveat

T-1ahypo alum sepia

Fixer and silver streamstated by the source

A bath built on 480 g of hypo in 2.8 L of water, holding silver from its own charge and from the prints, is a thiosulfate-and-silver stream rather than a toner stream: it belongs with the fixer waste and it is worth recovering. The alum is the only thing in it that a fixer bottle would not already contain.

Sources:Eastman Kodak Company, 1998§ Silver concentrations in photographic processing solutions · Eastman Kodak Company, 2006§ Toners Mixed from Formulas, Hypo Alum Sepia Toner T-1a, page 6

Argued in:T-1a, waste · The disposal caveat

T-21gold, warm brown

Hazardous collection onlystated by the source

A persulfate oxidiser, dissolved silver from the charge solution and gold, in a thiosulfate bath. Every component is a reason to collect the whole volume, and the gold is the one component worth recovering for its own sake rather than for the environment's.

Sources: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§ Chemical dangers; environmental data · Eastman Kodak Company, 1998§ Silver concentrations in photographic processing solutions

Argued in:T-21, waste · The disposal caveat

T-26gold, blue

Hazardous collection onlystated by the source

Thiourea's classification is what makes the spent bath a collected waste rather than a dilute gold solution, and the gold itself is a heavy metal in a stream that also carries the silver the toning displaced.

Sources:National Center for Biotechnology Information§ GHS classification; environmental fate · Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals

Argued in:T-26, waste · The disposal caveat

GP-1gold protective

Hazardous collection onlystated by the source

A small volume carrying gold and a thiocyanate. It is collected rather than discharged for the thiocyanate as much as for the metal, and its volume is the smallest of any bath in this matrix, which makes collection easy rather than optional.

Sources: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§ Chemical dangers; environmental data · Eastman Kodak Company, 1999§ Properly dispose of photographic processing chemicals

Argued in:GP-1, waste · The disposal caveat

T-55selenium, Level D

Hazardous collection onlystated by the source

Selenium is a cumulative toxicant and a regulated one, and there is no quantity of it this course would put into a drain. The cell is stated for completeness of the matrix rather than as a working instruction, because the formula is Level D and the course gives no procedure to produce the waste.

Sources: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, 1998§ Environmental data; toxicity of selenium compounds · Environment Agency, Natural Resources Wales and the Scottish Environment Protection Agency§ The classification of wastes containing selenium compounds

Argued in:T-55, waste · The Level D policy

Cost

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

Empty, and the emptiest column in the whole product. Toners are where a comparison matrix would most like to say something about cost, and this course's shopping data cannot yet support a single cell of it.

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 The price file prices silver nitrate and nothing else these baths are made of: no chloroauric acid, no sodium sulfide, no potassium alum, no selenium salt, no thiourea, no thiocyanate, no persulfate. The column is empty for the same reason as the fixers' cost column and cannot be filled from anywhere but the file. The one thing worth stating without a band is the order: a gold bath is dominated by the gold, and the fixers matrix's note on the missing thiosulfate price applies to T-1a and T-21 as well.

T-7asulfide sepia

Not established

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

T-52sulphide, 1949

Not established

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

T-1ahypo alum sepia

Not established

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

T-21gold, warm brown

Not established

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

T-26gold, blue

Not established

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

GP-1gold protective

Not established

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

T-55selenium, Level D

Not established

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