Foma FOMATOL LQN developer

This is a product page, not a formula page, and the difference is the point of it. Everything else in this library is a list of quantities with a source attached and an account of what each quantity is doing. Nobody outside Hradec Králové knows the quantities in this bottle. What follows is what its maker publishes, which for dilution, time, capacity and the physical properties of the concentrate is a good deal; what its maker’s own safety data sheet discloses, which is four substances and an instructive pair of silences; what the two documents together still leave unknown; and the open formula to mix if you would rather know than buy.

FOMATOL is a family name, not a product. Foma’s paper-developer sheet carries FOMATOL LQN, the phenidone–hydroquinone liquid concentrate this page is about; FOMATOL P, a two-bag phenidone–isoascorbate powder; and FOMATOL PW, a powder formulated for the Fomatone papers — and puts FOMA GD-L and FOMA UNIVERSAL DEVELOPER in the same table beside them. LQN is the one every Foma paper sheet names in its own tray table, and the one whose safety data sheet stands under a single product name rather than being split into a small bag and a large one, so it is the one documented here. Foma’s own safety-data-sheet index — which is on the Czech side of the site and is not linked from the English pages — carries sheets for FOMATOL LQN, for both bags of FOMATOL P in two formulations, and for both bags of a FOMATOL H that the technical datasheet does not mention at all. It carries none for FOMATOL PW.

FOMA BOHEMIA spol. s r.o., Hradec Králové — sold as liquid concentrate

Components the maker discloses — from the safety data sheet, which classifies hazards and does not state a formula

Component	Concentration as the sheet gives it	Hazard codes
Potassium carbonate (anhydrous)named on the sheet as Uhličitan draselnýCAS 584-08-7	< 12 %	H319, H315, H335
Hydroquinonenamed on the sheet as HydrochinonCAS 123-31-9One of the two developing agents Foma names — the technical datasheet calls FOMATOL LQN a phenidone-hydroquinone developer	< 5 %	H351, H341, H302, H318, H317, H400, H410
Potassium hydroxidenamed on the sheet as Hydroxid draselnýCAS 1310-58-3	< 1,5 %	H314, H302, H290
Diethylentriaminpentaoctan pentasodný (Dissolvine D88)CAS 140-01-2	< 0,5 %	H332, H319, H315, H361

Not disclosed. Foma publishes no composition for FOMATOL LQN. The safety data sheet names four substances and gives each an upper bound for the purpose of classifying a hazard, which is not an assay: every band is one-sided, so the sheet states no lower limit for anything, and the four upper limits together account for under a fifth of the bottle. The rest is water and whatever is present below the concentration at which the CLP rules require it to be named — including, on the maker's own evidence elsewhere in its literature, both a phenidone and a sulphite, neither of which appears in the composition table at all. No quantity, no ratio between the two developing agents, no alkali loading, no restrainer, no antifoggant, no working-solution pH, no keeping time for either the concentrate or the tray, and no formulation date appears in any Foma document. A reader who needs to change one term at a time, and see what it does, has to mix an open formula instead of buying this one.

Nearest open formula. Kodak D-72 — Both are alkaline superadditive paper developers for a dish at 20 °C, meant for every paper in the maker's range, and Foma's own paper sheets put them in the same class by naming Kodak Dektol among the foreign developers it considers interchangeable with this one. D-72 is published in full and mixed from five weighed chemicals whose functions can each be named; FOMATOL LQN is a bottle whose maker names two developing agents in a sentence and quantifies nothing. D-72 pairs metol with a fourfold excess of hydroquinone in sodium carbonate and dilutes one in four for bromide enlarging papers; FOMATOL LQN pairs a phenidone with hydroquinone in potassium carbonate stiffened with potassium hydroxide, adds a sequestrant that a 1928 formula has no equivalent for, dilutes one in seven, and publishes a capacity in square metres, a concentrate pH, a concentrate density and a machine dilution where Kodak's two printings give no pH and no capacity at all. What Foma does not publish and Kodak does is the thing itself: D-72 keeps three months as a stock and can be made in any volume you care to weigh, and this cannot be made at all.

Purpose

To develop a black and white print on any Foma paper to a neutral black in a minute or two at ordinary room temperature, from a bottle you measure rather than a powder you dissolve. Foma describes FOMATOL LQN as a “high-durable liquid concentrate of a phenidone-hydroquinone normal-working positive developer”, designed “for the manual and automatic processing of all sorts of black-and-white photographic papers”, diluted 1+7 by hand and 1+4 in a machine.

Four of those words are the whole product. Liquid concentrate: nothing to weigh, nothing to dissolve, no dust, and a 250 mL bottle that makes two litres of working solution — which is the smallest sensible batch any developer in this library offers, mixed or bought. Phenidone– hydroquinone: the classical superadditive pair, named by the maker and then never mentioned again. Normal-working: Foma’s own term of art, and it is a contrast statement — the same sheet sells FOMA GD-L as the “contrasting” concentrate for when normal is not what you want. High-durable: an adjective with no number behind it anywhere in Foma’s literature, and the single largest gap in what this maker publishes.

Recommended uses

Tray printing at 20 °C, at 1+7. That is the use Foma documents, the dilution every one of its paper sheets prints in its own processing table, and the one the published capacity belongs to.

On Fomabrom and Fomaspeed, for a neutral image tone. This is the maker’s own recommendation and it is made from the paper’s side rather than the developer’s: the Fomabrom and Fomaspeed sheets both say that for common work and a neutral image tone, Fomatol LQN or Fomatol P are recommended, and both then name the foreign developers they consider interchangeable — Kodak Dektol, ILFORD PQ UNIVERSAL, BROMOPHEN, Adox Neutol Liquid NE, Rollei Print Neutral ECO, Amaloco AM 6006, Moersch SE4 Neutral. A maker that prints its competitors’ product names on its own paper sheet is telling you something useful about how interchangeable it believes this class of bath to be.

On Fomabrom Variant, where the recommended company changes. The variable-contrast baryta sheet recommends Fomatol LQN, Fomatol P “or Universal developer FOMA” for common work over all contrast grades and a neutral image tone — and the foreign list beside it is a different list: ILFORD Multigrade, Kodak Polymax T, Adox MCC Developer, Rollei Print Neutral. Foma has swapped a list of general paper developers for a list of variable-contrast ones, while keeping both of its own and adding a third — which is worth noticing before you conclude that a graded-paper developer and a variable-contrast paper developer are different kinds of bath. On this maker’s evidence they are the same bath, recommended twice.

On Fomatone MG Classic, as the least warm of the three Fomatols. The Fomatone sheet recommends Fomatol LQN, Fomatol P and Fomatol PW together “for their brown-green and warm-brown image tone respectively”, and adds that the last of the three “having specially been formulated for this paper”. Three developers and two colours is a sentence that does not quite parse, and the course will not allocate the tones for Foma; what is unambiguous is that PW is the paper’s own developer and that LQN is offered as an alternative to it.

In a roller processor at 1+4, replenished. Foma publishes a replenishment rate — 200 mL of ready-to-use developer at 1+4 per square metre of paper — which is more than most makers say about machine printing, and it is the only reason the 5 litre canister exists.

Where a small quantity is the point. The 250 mL bottle is the answer to the constraint that governs BROMOPHEN: a powder carton cannot be split and its smallest batch is a litre of stock, whereas 125 mL of this concentrate makes exactly one litre of tray solution and the rest of the bottle stays capped.

When another formula is preferable

• When you want to understand a print developer rather than use one, mix D-72. It is the same job done by five chemicals you can name, weigh and change, and it is the comparison this page is built around.
• When you want a warm image tone from a formula you control, D-156 cuts D-72’s alkali to a quarter and raises the bromide, and D-166 goes further with twelve and a half grams of bromide to the litre. Foma’s own answer is FOMATOL PW, which this course cannot teach because its composition is not published either.
• For soft, open highlights with the restrainer in your hands rather than the bottle, D-52 publishes four bromide doses to be added at the tray, one for each paper — the exact opposite of buying a bath whose restrainer, if it has one, is not named.
• When one bath has to do papers and film, D-163 is published for both and PQ UNIVERSAL is sold for both. FOMATOL LQN is a positive developer and Foma offers FOMA UNIVERSAL DEVELOPER, a separate two-bag powder, for negatives.
• When you need to know how long the bath will keep. This is the reason to mix rather than buy that applies hardest here. Every open formula in this library carries a keeping figure from its source; the maker of this one publishes none, for the bottle or for the tray.
• When the darkroom is not at 20 °C. Every tray figure Foma publishes is at 20 °C and the only other temperature in its literature is 30 °C inside a machine. There is no published route between them.

What the maker publishes

A concentrate gives its maker less to say than a powder does — there is no mixing procedure to write — and the surprise here is how much of what Foma does publish is in the paper sheets rather than the developer sheet.

Two dilutions, and what each is for. Manual processing: one part concentrate to seven parts water. Automatic processing: one part to four. Both are on the developer sheet, in the FOMATOL LQN entry, and nothing else about strength appears anywhere.

A capacity, in square metres. One litre of ready-to-use developer at 1+7 develops 1.5 m² of baryta (FB) paper or 3 m² of resin-coated (RC) paper. That is an unusual unit for a hand printer and a natural one for a machine, and it is the only capacity figure Foma gives.

A replenishment rate. 200 mL of ready-to-use developer at 1+4 per square metre of paper, for automatic processing. There is no replenishment scheme for the tray.

Packaging. A polyethylene bottle of 250 mL and a polyethylene canister of 5 litres.

Times, for six papers, at 20 °C. The developer sheet’s table gives the FOMATOL LQN column as: Fomabrom 90–120 s; Fomabrom Variant 100–130 s; Fomaspeed 60–90 s; Fomaspeed Variant 60–90 s; Fomatone MG Classic 90–180 s; Retrobrom Sp 120–240 s.

The same times again, on the papers’ own sheets, with the dilution attached. This is where the developer sheet’s gap is filled. Fomabrom, Fomabrom Variant, Fomaspeed and Fomatone MG Classic each print a full processing table naming Fomatol LQN (1+7) with the same time, and Fomaspeed adds a machine row: Fomatol LQN (1+4), 25–35 seconds at 30 °C, which is the only place in Foma’s literature where the machine dilution acquires a time and a temperature.

The physical properties of the concentrate, from the safety data sheet. A yellowish liquid at 20 °C with a mild, non-specific odour; pH about 10.5 to 11 at 20 °C; relative density 1.27 g/cm³ at 20 °C; non-flammable; freezing a little below 0 °C and boiling a little above 100 °C; soluble in water and not in non-polar solvents. Those are control measurements you can make on your own bottle, and no other Foma document contains them.

A statement of what is incompatible with it, which is rarer than it sounds. Section 10 names strong mineral acids as the hazardous reaction, high temperature as the condition to avoid, and aluminium as the incompatible material. Compare ILFORD’s sheets for the same class of product, which record incompatible materials as “Not known”.

A waste route, with European codes. 09 01 01* (aqueous developer solutions) and 15 01 10* (packaging containing residues of dangerous substances), not to be disposed of with municipal waste and not to be flushed to the drain.

🧮Turning square metres into sheets, which the maker does not do for you

Foma’s capacity is in area and every printer’s capacity is in sheets, so the conversion has to be made before the figure means anything. An 8 × 10 inch sheet is 0.2032 m × 0.254 m, which is 0.0516 m².

At 1+7, one litre of working solution covers 3 m² of resin-coated paper, so it covers 3 ÷ 0.0516 ≈ 58 8 × 10 RC sheets. On baryta it covers 1.5 m², so ≈ 29 sheets. In A4 (0.0624 m²) the same litre is about 48 RC sheets or 24 FB. A 250 mL bottle at 1+7 makes two litres of working solution: about 116 RC or 58 FB sheets of 8 × 10 in total.

All of those numbers are the course’s arithmetic on Foma’s published area figures, and Foma states none of them. Set them beside ILFORD’s published print capacity for BROMOPHEN — 70 RC and 45 FB 8 × 10 sheets per litre of working solution — and Foma’s litre is the smaller on both bases, and much the smaller on fibre, where its ratio of RC to FB capacity is a flat two to one against ILFORD’s roughly three to two.

Do not read that as a statement about which developer is more economical. The two litres are not the same thing: ILFORD’s holds 250 mL of a stock solution and Foma’s holds 125 mL of a concentrate whose strength is not published. What is comparable is what each maker says a litre in your tray will do, and that comparison is the one above.

!Two of the maker's own sheets, one paper, and half a minute between them

Foma’s developer sheet gives Fomatone MG Classic in FOMATOL LQN as 90–180 seconds at 20 °C. The Fomatone MG Classic paper sheet gives the same paper in the same developer at 1+7 as 1–3 minutes at 20 °C.

Three minutes and 180 seconds agree. One minute and 90 seconds do not, and the disagreement is a third of the shorter figure. Every other row matches exactly: Fomabrom 90–120 both times, Fomabrom Variant 100–130 both times, Fomaspeed 60–90 both times. Only the warm-tone paper’s minimum differs.

The course does not know which sheet is right and will not average them. Use the longer minimum, because on a warm-tone chlorobromide paper the cost of underdevelopment is a print that is thin, warm and blotchy rather than merely light, and because 90 seconds is inside 1–3 minutes while 60 seconds is outside 90–180. Then run the test at the foot of this page and find out which of Foma’s two numbers describes your paper.

What is not disclosed

The formula. Not the quantity of any ingredient, not the ratio between the two developing agents, not the alkali loading, not the restrainer, not the antifoggant, and not the date the current formulation was fixed. Foma names two developing agents in one sentence of a product description and stops.

The working solution. Everything Foma measures, it measures on the concentrate. The pH of 10.5 to 11 is the pH of the bottle; the density of 1.27 g/cm³ is the density of the bottle. Neither the 1+7 tray solution nor the 1+4 machine solution has a published pH, a published density or a published keeping time. The number you would actually meter in the dish is not in any Foma document.

Any keeping figure at all. This is the largest silence on the page and it has no equivalent elsewhere in this library. The technical datasheet says “high-durable” and stops. The safety data sheet asks for storage in the original container in a dry cool place away from foodstuffs and gives no time. There is no shelf life for the sealed bottle, no life for the opened bottle, no life for the tray and no life for a capped bottle of working solution. For comparison, ILFORD publishes six such figures for BROMOPHEN on one page.

A tray temperature other than 20 °C, and any guidance on how to move between the tray and the machine. 20 °C for the hand and 30 °C in the roller are two isolated points.

Two substances the maker’s own documents say are there. The composition table names four substances. The product description names a phenidone, which is not one of them. Sections 5.2 and 10.6 warn that sulphur dioxide may be evolved at elevated temperature and on reaction with acids, which is the signature of a sulphite or bisulphite, and no sulphite is in the table either. Those are the two silences the next callout is about.

!Why the four bands cannot be added up — and cannot be subtracted from either

A composition table with four numbers in it invites the same arithmetic every time, and here the invitation is unusually strong because the numbers are small and the remainder looks solvable. Doing the sum once is the cure.

Every band on this sheet is one-sided: less than 12, less than 5, less than 1.5, less than 0.5. There is no lower limit for anything, so the sheet is consistent with a bottle containing 11.9 per cent potassium carbonate and with one containing a trace. Add the four upper limits and you get about 19 per cent — which is not a shortfall to be explained, because none of the four is stated to be present in any particular amount at all. The table’s own foot says what most of the rest is: vodný roztok, an aqueous solution.

Now try the subtraction that the arithmetic seems to offer. Eighty-one per cent of the bottle is unnamed; the maker’s own product description puts a phenidone in there; the maker’s own sections 5.2 and 10.6 put a sulphite in there; and the sheet gives no upper bound, no lower bound and no classification for either, because a substance below the concentration at which CLP requires it to be named simply does not appear. You cannot compute what is not there from what is, and a page that tried would be reconstructing a formula out of a hazard document.

That is not sloppiness on Foma’s part. A concentration band on a safety data sheet exists to support a classification — section 16 records that this mixture was classified by the calculation method — and a band chosen for that purpose is far too coarse to mix from. A safety data sheet read as a hazard document is evidence. Reassembled into a recipe it is a fabrication with citations attached, and this page does not attempt it.

Nothing about why. No source in the corpus says why Foma uses potassium salts where every Kodak paper formula in this library uses sodium, why the concentrate sits at 10.5 to 11 rather than higher or lower, when the sequestrant was put in, or what separates FOMATOL LQN’s tone from FOMATOL P’s on the same paper. Those are the interesting questions and the literature does not touch them.

Disclosed components

Every component in the table above, in the order the safety data sheet prints them, with the concentration each is given as an upper bound on its share of the concentrate — not of the tray. The sheet is in Czech and the names below are its own; the CAS number is the field that travels.

Uhličitan draselný, CAS 584-08-7, less than 12 per cent. This is potassium carbonate, the alkali, and it is the first and largest entry on the sheet. The CAS the sheet prints is the anhydrous salt’s, which is what a supplier ships; in a solution the hydration state of the solid that went in is not a property of the liquid. Carbonate against bicarbonate is a genuine buffer pair, and a buffer is what a print developer needs: a tray open to the air must hold its pH through several square metres of paper, each sheet of which puts acid into the bath as it develops. The identification of the carbonate as the buffering alkali is the course’s reading of a component list; Foma does not say it. The sheet classifies it H319, H315 and H335, and section 8.1 quotes a Czech workplace limit for it of PEL 5 mg/m³.

The choice of the potassium salt rather than the sodium one is the first thing on this sheet that distinguishes the product from every open paper formula in this library, all of which use sodium carbonate. Potassium carbonate is far more soluble than sodium carbonate, which is exactly what a concentrate needs and a powder does not, and Part XVIII’s print developer chemistry is where the alkali’s job is set out. That the cation was chosen for solubility in a concentrate is the course’s inference and not a Foma statement.

Hydrochinon, CAS 123-31-9, less than 5 per cent. This is hydroquinone, and here the maker does tell you what it is for: the product description calls FOMATOL LQN a phenidone-hydroquinone developer. It carries almost all of the mixture’s classification — H351, H341, H302, H318, H317, H400 and H410 — and it is the substance that gives the product the signal word Nebezpečí, Danger. It is also the substance the transport classification is written around: section 14 names the load UN 3082, environmentally hazardous substance, liquid, n.o.s. (hydroquinone), class 9, packing group III, and a marine pollutant. Section 8.1 quotes the Czech workplace limits, PEL 2 mg/m³ and NPK-P 4 mg/m³, and section 12 gives an LC50 for fish of 0.15 mg/L. It is the second entry in the table and the only one carrying an EU index number for a harmonised classification, 604-005-00-4.

Hydroxid draselný, CAS 1310-58-3, less than 1.5 per cent. Potassium hydroxide is the third entry, it is one of the two substances Foma names on the label — “Obsahuje: hydrochinon, hydroxid draselný” — and it is the component that makes this concentrate different in kind from a mixed stock solution. A carbonate alone does not take a solution to pH 11; a caustic alkali alongside it does, and it also lets a great deal more of the developer be packed into a small bottle. As a substance it is Skin Corr. 1A, H314, with H302 and H290; the mixture as a whole is classified only Skin Irrit. 2, because the hydroxide is present below the concentration at which it would make the mixture corrosive. That the hydroxide is there to raise and hold the concentrate’s alkalinity is the course’s reading of where a caustic alkali sits in developer formulation, and Foma states no function for it. Part VIII on alkalis, buffers and pH is the chemistry, and the practical consequence is on this page’s safety section: H290 is what makes the aluminium warning in section 10.5 mean something.

Diethylentriaminpentaoctan pentasodný (Dissolvine D88), CAS 140-01-2, less than 0.5 per cent. The smallest entry and the most interesting one, and the only one the sheet gives a trade name as well as a chemical one. This is pentasodium diethylenetriaminepentaacetate, a chelating agent from the same family as the EDTA salts the course meets elsewhere, and complex formation is Part III’s subject. It has no photographic role except sequestration: locking up calcium, magnesium and above all iron so that hard water does not throw a scum into the tray and traces of iron do not catalyse the aerial oxidation of the developing agents. Reading it as an answer to hard water and to metal-catalysed oxidation is the course’s inference; Foma states no function for it at all, and the course has no page for the substance itself.

Two things about this line are worth recording rather than smoothing over. The first is that HARMAN discloses the same substance, by the same CAS number, in PQ UNIVERSAL — two makers in two countries, one sequestrant, and neither of them says why. The second is that the sheet names it inconsistently: section 3.2 calls it the pentasodium salt and sections 11 and 12 give toxicological and ecotoxicological data for the pentapotassium salt. Those are different substances with different CAS numbers, and the sheet prints only one CAS number, in section 3.2. Record the discrepancy when you file the sheet — the procedure is recording a safety data sheet — and trust the composition table’s CAS over the toxicology section’s name.

⚗The two substances the composition table does not name

This is the most instructive thing on the sheet, and it is a lesson in what a safety data sheet is for rather than a discovery about the product.

Phenidone. Foma’s technical datasheet calls FOMATOL LQN a phenidone-hydroquinone developer. The composition table names no pyrazolidone. Both documents are Foma’s and neither is wrong: a mixture’s composition table lists the substances that drive its classification, and a substance present below the relevant CLP cut-off is not listed. The course’s reading is that the phenidone is present at a concentration too low to require naming, which is exactly what superadditivity predicts and what Part VIII’s lesson explains — a very small quantity of the fast agent transforms the behaviour of a much larger quantity of the slow one. Phenidone has its own encyclopaedia page; its concentration in this product is not published and no number on this page bears on it.

A sulphite. Section 5.2 warns that “at elevated temperature, or on contact with acid, sulphur dioxide may be released”, and section 10.6 repeats it among the hazardous decomposition products. Liberating sulphur dioxide on acidification is what a sulphite or a bisulphite does, and a developer with no preservative in it would not survive a week in a bottle. That a sulphite is present is the course’s inference from a hazard statement, and the quantity is unknown and unknowable from this document. Part VIII on sulfite and preservation is the chemistry; sodium sulfite is the entry, and the course does not even know which cation Foma used.

The practical upshot is one line long and it is on the safety section below: do not put an acid stop bath into a container that has developer in it. The maker has told you what comes off if you do.

Behaviour

It is the fastest bath in this library’s paper section, and the paper is doing some of the work. Sixty to ninety seconds on Fomaspeed is half of what D-72 asks on a bromide enlarging paper and half of BROMOPHEN’s two minutes on resin-coated. But the Fomaspeed sheet says in its own opening paragraph that developing agents incorporated in its emulsion are what shorten manual development to that figure. On the baryta papers, which have no incorporated agents, the same developer takes 90 to 130 seconds. A published time is a property of a paper and a developer together, and Foma has stated that in writing about its own product.

It develops to completion, not to a density you choose. This is the largest single difference between printing and film processing, and it is where beginners lose prints. Foma gives ranges rather than single figures — 90 to 120 seconds, 100 to 130 — and a range of that shape says the working point sits on a plateau. A sheet lifted early does not read as lighter; it reads as thin, weak in the blacks and blotchy wherever the solution first reached the paper. Part XVIII on maximum black is where the two curves that make that true are drawn.

It exhausts by area, and you have to do the conversion yourself. Three square metres of RC or one and a half of FB to the litre — roughly 58 and 29 8 × 10 sheets by the arithmetic above. Count sheets rather than judging the colour of the tray, and remember the halving on fibre: baryta soaks up far more solution and carries more of it away.

It has no published clocks at all, which is a behaviour in itself. The unopened bottle, the opened bottle, the tray and a capped bottle of working solution all have the same published life: none. In the absence of a figure, the honest working assumption is the one every other maker’s figures point at — mix the tray for the session and pour it away at the end of it, and treat a part-used bottle of concentrate as something to use up rather than to keep. That is the course’s advice from the general behaviour of alkaline developer concentrates, and it is not Foma’s.

It is formulated for two temperatures and published for two dilutions, and the four do not interchange. 1+7 at 20 °C in a tray; 1+4 at 30 °C in a machine. There is no published time for 1+4 in a tray, none for 1+7 in a machine, and none for either at any other temperature.

⚗What the published pH is actually telling you

About 10.5 to 11 for the concentrate is a strongly alkaline solution, and every pH unit is a factor of ten in hydroxide-ion concentration. That alkalinity is what makes a print develop in ninety seconds where a film in a borax-buffered bath takes ten minutes, and Part VIII’s lesson on alkalis and buffers works through why: a developing agent works as its anion, and the fraction ionised is set by the pH against the agent’s pK_a.

The catch specific to this product is that the figure is for the bottle and the tray gets the 1+7 dilution, for which Foma publishes no pH. Diluting a carbonate-buffered solution eightfold does not divide its pH by anything — resisting that is what a buffer is for — but a caustic alkali is not a buffer, and the course will not print a number the maker does not give. Use the band as a control measurement on your own fresh concentrate, with a meter calibrated that day, and measure your own working solution to find out what yours actually is. The density is the cheaper check of the two: 1.27 g/cm³ at 20 °C needs only a measuring cylinder and a balance.

Image characteristics

Image tone: neutral, on the papers Foma recommends it for. This is the maker’s own claim and it is made three times, on the Fomabrom, Fomabrom Variant and Fomaspeed sheets, each time in the form “for common work and a neutral image tone”. It is a claim about the product rather than a measurement, and it is worth noticing that Foma makes it about two of its own developers at once — LQN and P — which is a statement that the choice between them is not a choice about colour.

On a warm-tone paper it is the cool option. The Fomatone MG Classic sheet recommends all three Fomatols “for their brown-green and warm-brown image tone respectively” and says PW was formulated for that paper. The same sheet warns that “any developers giving more expressed images usually reduce contrast and the yield of speed”, and that the paper base itself is coloured to match the developed silver. On that paper the developer is one of three things setting the colour, and it is not the dominant one. Part XVIII on paper emulsions, image tone and speed is the lesson.

Contrast: not something this tray decides. Foma sells a different concentrate, FOMA GD-L, when contrast is the variable — “a contrasting phenidone-hydroquinone developer”, 1+2 for papers with a range of 1+1 to 1+4 given for it, against this one’s single 1+7. On a variable-contrast paper the grade is set by the filter and the exposure, which is what makes split-grade printing reproducible from one sheet to the next.

Fog: no claim is made. Foma says nothing about clean working, base white or fog, and — unlike ILFORD — names neither a bromide nor an organic antifoggant on its sheet. Whether this developer contains a restrainer is not known. If your whites go grey, the diagnosis below does not start with the bath.

Grain, acutance and film speed do not apply. This is a positive developer; Foma sells FOMA UNIVERSAL DEVELOPER and the Fomadon range for negatives.

The mechanism

Everything in this section that goes beyond the maker’s own two sentences is marked as what it is.

What the maker states. FOMATOL LQN is a phenidone–hydroquinone normal-working positive developer supplied as a liquid concentrate, diluted 1+7 by hand and 1+4 in a machine, developing a print in sixty seconds to four minutes at 20 °C depending on the paper, with a concentrate at pH 10.5 to 11 and a relative density of 1.27, containing potassium carbonate, hydroquinone, potassium hydroxide and a pentasodium DTPA sequestrant in the four amounts the safety data sheet bounds from above.

What follows from that without needing anything else: it is a PQ developer. A pyrazolidone with hydroquinone is the classical form of the superadditive pair, and the pair is the central mechanism of Part VIII’s superadditivity lesson. The fast agent — here Phenidone — reduces silver at the latent-image site and is itself oxidised; the hydroquinone, present in much the larger quantity, regenerates it from solution. The consequence a printer can see is that a very small amount of one substance transforms the behaviour of a much larger amount of another — which is consistent with the hydroquinone being bounded at 5 per cent on the sheet while the phenidone does not appear on it at all. A bound on one substance and a silence about another are not a ratio, and this page does not treat them as one.

Why the alkali is in two parts. A carbonate and a caustic alkali together give a solution that is both strongly alkaline and buffered: the hydroxide sets the level, the carbonate holds it while the tray does its work and acid accumulates. That reading is the course’s, from where those two substances sit in developer formulation generally. Foma prints two rows of a hazard table and explains nothing.

Why the sequestrant matters more in a concentrate than in a powder. A powder has no water in it and nothing to go wrong until you mix it. A concentrate sits in a bottle for months in contact with its own dissolved oxygen, and traces of iron catalyse the oxidation of developing agents. A chelating agent locks those traces up. This is the course’s inference and not a Foma statement, and it is the most plausible reading of why a 2016 liquid contains something no 1928 powder formula does — see Part III on complex formation.

Inference, labelled as inference. The regeneration account of superadditivity is the standard one and no source in this corpus states it for this product. The identification of potassium carbonate as the buffering alkali, of potassium hydroxide as the alkalinity-setter, of DTPA as a sequestrant, of a phenidone below the CLP cut-off, and of a sulphite behind the sulphur-dioxide warning are all readings of what those substances do in developers generally. None of them is a Foma statement, and none of them carries a quantity.

What is unknown and stays unknown. The ratio of phenidone to hydroquinone. Whether there is a restrainer at all. Whether there is an organic antifoggant. The sulphite loading. What fills the four fifths of the bottle that nothing names, beyond the sheet’s own vodný roztok. The working pH. Anything at all about keeping. Why FOMATOL P uses isoascorbate where this one uses hydroquinone, which is the most interesting question the sheet raises and the one Foma answers least.

!Reading a safety data sheet in a language you do not have

This sheet is published only in Czech, and it is the only sheet in this course’s corpus that is. Two things follow, and both are general skills rather than facts about Foma.

The structure is the same in every language, because the law fixes it. Sections 1 to 16 are the same sections in the same order in every REACH safety data sheet ever written. Oddíl 3, Složení is section 3, composition, wherever you find it; oddíl 9 is physical and chemical properties; oddíl 13 is disposal. You can read the parts of a sheet that matter without reading the language, because the numbers, the CAS registry numbers, the H-statements and the P-statements are the same tokens everywhere. The course’s page on GHS and CLP is where those tokens are decoded.

Trust the CAS number over the name, always. That is true of an English sheet too — ILFORD’s own sheets run three synonyms of hydroquinone together with no separator between them — and it is what saves you here. Uhličitan draselný is 584-08-7 whether or not you can pronounce it.

The one thing a translation will not rescue you from is a sheet that names a substance two different ways in two different sections, as this one does with its sequestrant. That is caught by comparing sections, not by comparing languages.

The nearest open formula

Kodak D-72, and the comparison is the reason this page exists.

D-72 is the archetype alkaline paper developer: metol and a fourfold excess of hydroquinone in sodium carbonate, with potassium bromide as the restrainer, mixed from five weighed chemicals into a stock and diluted one in four for bromide enlarging papers. FOMATOL LQN is the same class of bath doing the same job on the same kind of paper, with a pyrazolidone in place of the metol, potassium salts in place of sodium ones, a sequestrant that D-72 has no equivalent for, and a bottle in place of a balance. Foma’s own paper sheets put the two in the same class, by naming Kodak Dektol among the foreign developers it considers interchangeable with this one — though the course has no source stating what Dektol contains, so the comparison below is made against Kodak’s published formula and not against Kodak’s product.

	Kodak D-72	Foma FOMATOL LQN
Composition	Published in full, twice, twenty-one years apart	Not published
Developing pair	Metol and hydroquinone, both weighed	A phenidone and hydroquinone, both named by the maker, neither quantified
Alkali	Sodium carbonate, quantity published	Potassium carbonate and potassium hydroxide named; no quantity, and that they buffer is inferred
Restrainer	Potassium bromide, quantity published	None named; whether one is present is not known
Sequestrant	None	Pentasodium DTPA, under 0.5 % of the concentrate
Sold as	Five chemicals you weigh	A 250 mL bottle or a 5 L canister
Smallest batch	Whatever you choose to weigh	125 mL of concentrate, for one litre of tray solution
Working dilution	1:4 for bromide enlarging papers	1+7 by hand, 1+4 in a machine
Published pH	None, in either printing	10.5 to 11, for the concentrate only
Published density	None	1.27 g/cm³ at 20 °C, for the concentrate
Published paper time	1½ minutes at 1:4 on bromide enlarging paper, at 21 °C	60 seconds to 4 minutes at 1+7, by paper, at 20 °C
Capacity	None published in either Kodak printing	3 m² RC or 1.5 m² FB per litre of working solution
Keeping	Stock 3 months full, 1 month half-full	Nothing published, for anything
What you can change	Any of five quantities, one at a time	The dilution, the time and the temperature

The last three rows are the whole argument. Buying the bottle gets you a published capacity, a published concentrate pH and density, a machine dilution, six papers’ times from the maker’s own laboratory, and exactly three variables. Mixing D-72 gets you a bath with no published capacity and no published pH, and eight variables, five of which are quantities you chose — in any volume you like, and with a keeping figure you can plan around. Part XVIII’s comparison session puts the two in adjacent trays with the same negative, which is the only way to find out what the difference is worth to you.

Safety

Level B, and the reasoning belongs on the page rather than in a database.

Foma’s classification of the mixture is Carc. 2 (H351), Muta. 2 (H341), Skin Sens. 1 (H317), Eye Dam. 1 (H318), Skin Irrit. 2 (H315), Aquatic Acute 1 (H400) and Aquatic Chronic 2 (H411), with the signal word Nebezpečí — Danger. Skin sensitisation is what pushes it past Level A on the classification rubric: sensitisation is not reversible, and a Level A page assumes substances that are at most irritant at the concentrations handled. Eye Dam. 1 — serious eye damage, not irritation — is what makes splash goggles rather than spectacles the right answer, and splash goggles are a Level B assumption. The suspected-mutagen and suspected-carcinogen classifications are read against the Level C criterion and do not meet it, because that criterion turns on a fume cupboard or specialist disposal being the recognised control, and Foma’s own control is ventilation, gloves, eye protection and working clothing. Level B.

No dust, and that is the real difference from a powder developer. Section 8.2 states that respiratory protection “is not needed in normal handling” — a sentence neither ILFORD powder sheet in this corpus contains. A liquid concentrate removes the one hazard a two-bag powder cannot avoid. What it puts in its place is a splash of something at pH 11.

Personal protection, as the sheet specifies it. Rubber gloves; goggles or a face shield; working clothing. Local exhaust ventilation and running water for washing eyes, hands or contaminated skin, present at the workplace. Do not eat, drink or smoke while handling it; keep it away from food and drink; wash your hands with soap and water afterwards; take off contaminated clothing. The course’s glove selection page is where breakthrough time is taken from the glove maker rather than assumed.

Tongs, on every print. Sensitisation is built out of many small contacts rather than one memorable splash, and an evening spent lifting sheets out by hand is far more skin exposure than a spilt tray would ever give. The sheet classifies the mixture itself, not merely one of its components, as a skin sensitiser and a skin irritant.

Eyes first, and do not neutralise. The sheet’s first-aid instruction for eyes is to remove contact lenses, flush with water as soon as possible, force the lids open if they are clamped shut, avoid contaminating the unaffected eye with the washings, and — in the sheet’s own emphasis — do not attempt neutralisation. That is the right instruction for an alkali and it is the one on the course’s eyewash procedure. For swallowing, the sheet asks for the mouth to be rinsed and about 40 mL of cold water to be drunk as a dilution, with no vomiting induced, no activated charcoal and no neutralising agent.

Published exposure limits, quoted by the sheet from the Czech regulation NV 361/2007 Sb.: hydroquinone at PEL 2 mg/m³ with a ceiling of 4; potassium hydroxide at PEL 1 mg/m³ with a ceiling of 2; potassium carbonate at PEL 5 mg/m³ with a ceiling of 10. Those are workplace air limits for the pure substances and none of them is a limit for a tray of diluted paper developer; they are here because the sheet prints them, and because a reader comparing this sheet with an ILFORD one should know that the two are quoting different national lists.

⚠The acid stop bath, and the one thing this sheet tells you that most do not

Section 5.2 and section 10.6 both say the same thing: sulphur dioxide may be evolved at elevated temperature and on reaction with acids.

In a darkroom the acid is never far away. The stop bath in the next tray is 2 per cent acetic acid, or Fomacitro at 1+19, and the acid fixer after it is acid too. Foma is not warning you about the tray sequence — a splash of stop into a tray of 1+7 developer is a small quantity of acid into a large volume of dilute alkali — but about the concentrate: an acid poured into a bottle or a funnel that still holds it, or a waste container into which developer and stop have both been tipped.

So: keep the concentrate away from acids, never pour stop bath into a developer bottle or a shared waste container, and rinse a funnel between baths. Sulphur dioxide is an acute respiratory irritant and a darkroom is a small room.

Storage

The concentrate, in its original bottle or canister, in a dry cool place, away from foodstuffs. That is the whole of Foma’s storage instruction, and there is no keeping time attached to it — not for a sealed bottle, not for an opened one. The technical sheet’s “high-durable” is an adjective and the safety data sheet’s section 10 says only that the product is stable under normal conditions and that high temperature is the condition to avoid.

In the absence of a figure, buy the size you will use. The 250 mL bottle makes two litres of working solution and the 5 litre canister makes forty. The course’s advice, not Foma’s: for hand printing the small bottle is the right purchase even at a worse price per litre, because a part-used bottle of alkaline concentrate with no published life is a liability and a sealed one is not. Decanting a dwindling concentrate into a smaller full bottle is the standard answer to the air above the liquid; Foma does not suggest it and neither does any other document in this corpus for this product.

The working solution is not stored at all. No life is published for it at either dilution. Dilute what the session needs, use it, and pour it away when the session ends.

Freezing is a real risk and the sheet quantifies it. Section 9.1 gives the freezing point as “slightly below 0 °C”. A concentrate this heavily loaded will not survive a night in an unheated outbuilding without at least dropping some of its solids, and a stock that crystallised in cold storage is the entry for what to do about it — warmth and patience, not a fresh bottle.

Label everything, with the product, the dilution and the date, using the labelling SOP — and for this product label the concentrate bottle with the date you first opened it, because that is the only clock anyone can give you and you are giving it to yourself. A tray of clear liquid in a darkroom is indistinguishable from three other trays of clear liquid, and an unlabelled or undated container is the failure that costs a whole printing session. The stock rotation SOP is where an undated bottle stops being a recurring problem.

Incompatibilities

Aluminium. Foma names it, in section 10.5, as the incompatible material — and it is the only maker in this corpus that names one at all for a paper developer. The chemistry is on the sheet’s own composition table: potassium hydroxide is classified H290, may be corrosive to metals, and aluminium is attacked by alkali with the evolution of hydrogen. So: no aluminium jug, no aluminium funnel, no aluminium tray, and no aluminium ladle stirred into a bottle of concentrate. Stainless steel, polyethylene, polypropylene and glass are all fine.

Strong mineral acids, which section 10.3 gives as the hazardous reaction, and acids in general — see the safety callout above. This is not merely a matter of neutralising the bath: acid carried back on a pair of tongs drops the tray out of the pH region in which a phenidone–hydroquinone pair works at all, and acid meeting the concentrate liberates sulphur dioxide.

High temperature, which section 10.4 gives as the condition to avoid, and which the same two sections tie to the same decomposition product.

Fixer, in both directions. A splash of thiosulfate in the developer tray dissolves silver out of the image and leaves a stain behind it; developer carried the other way exhausts the fixer sooner and stains the print at the far end of the sequence instead. Foma’s own paper sheets are built to prevent exactly that: every one of them puts a stop bath between the two and gives it a time — 2 per cent acetic acid or Fomacitro at 1+19, for 20 to 30 seconds on the baryta papers and 10 to 20 seconds on Fomaspeed. Fomacitro is another bought product whose composition Foma does not publish; the open bath this course teaches for that step is the citric acid stop bath.

Oxidisers of any strength, and toner chemistry above all. A print developer and a ferricyanide bleach are two things that must never share a shelf, a funnel or a waste bottle, and the same goes for dichromate, permanganate and persulfate. The pairs, and the reaction behind each of them, are on the chemical incompatibilities page; the practical rule in a printing darkroom is that toning and reduction chemistry lives at the other end of the bench from the developer bottle.

Waste

Bottled separately, and never down the drain. Foma’s section 13 is unusually direct about this: the product “must not be disposed of with municipal or other waste” and “do not flush into the sewer”. Spilt product is to be soaked into an inert absorbent and handed to an authorised person for disposal. Section 6.2 asks that the product be kept out of soil, drains, surface water and groundwater, and that a large release be reported to the emergency services.

The European waste codes, which are worth knowing because a waste contractor asks for them. 09 01 01* — aqueous developer solutions. 15 01 10* — packaging containing residues of dangerous substances. The asterisk marks them as hazardous waste in the European List of Waste.

Why the environmental classification is severe. The mixture is Aquatic Acute 1 (H400) and Aquatic Chronic 2 (H411), and the reason is on the composition table: hydroquinone carries an acute multiplying factor of 10, and section 12 records an LC50 for fish of 0.15 mg/L and a 21-day NOEC for daphnia of 0.0057 mg/L. It is also why the transport entry is UN 3082, environmentally hazardous substance, and why the load is a marine pollutant.

Empty bottles. Foma’s advice is that a thoroughly rinsed empty container may be reused or put out for plastics recycling, and it adds a sentence worth quoting and then qualifying: any slight hydroquinone residue left in a rinsed empty container “passes by oxidation into the harmless quinone form”. The course records the sentence and does not repeat the adjective. What is true in it is that the residue does not remain hydroquinone; 1,4-benzoquinone is not a harmless substance in general terms, and the case being described is a trace in a rinsed bottle rather than a quantity in a jar. Rinse the bottle into your own waste container, not into the sink, and let the rinsings go the same way as the bath.

The disposal caveat governs, and the rule where you live decides. The general chemical waste SOP is the procedure this course follows. Under any jurisdiction the developer bottle and the fixer bottle stay apart, because the fixer is worth something at a refiner and this bath is not.

Troubleshooting

Prints thin in the blacks, warm, and patchy. Nine times in ten this is development cut short rather than a fault in the bath; muddy print from snatched development sets out the whole diagnosis. Give it the published time for your paper — and on Fomatone MG Classic take the longer of the maker’s two minima — and change the exposure instead.

Highlights going grey and flat towards the end of a session. That is developer exhaustion, and with this product the check needs arithmetic first: three square metres of RC to the litre is about 58 8 × 10 sheets, and one and a half square metres of FB is about 29. Count sheets against that before you blame anything else. Exhausted developer is the general entry.

Prints from one session do not match prints from the next. Check the dilution first: 1+7 is 125 mL of concentrate into 875 mL of water, not 125 into a litre, and a misread dilution ratio changes both the time and the capacity. This developer is more exposed to that error than most, because its two published dilutions are 1+7 and 1+4 and the wrong one is a plausible mistake rather than an absurd one. Then check the temperature. Then check how long the bottle has been open. If the drift is gradual through one evening rather than between sessions, it is session exposure drift and the bath is not the cause.

Grey where the paper should be white. Two candidates, told apart by putting a strip of unexposed paper straight into the developer. Developer fog on paper is the developer’s fault; safelight fog and paper storage fog are not. Note that Foma names no restrainer and no antifoggant on its sheet, so unlike the ILFORD products there is no disclosed reason to expect this bath to be particularly good at holding a white — and no reason to expect it to be bad either. Test rather than assume.

The concentrate has gone dark in the bottle. Oxidation of the developing agents, which is what oxidised developer covers. With no published shelf life to appeal to, a darkened concentrate is your only evidence: test it against a control strip before a print you care about goes in it.

Crystals or a haze in the bottom of the bottle after a cold night. See stock crystallised in cold storage. The concentrate freezes a little below 0 °C by the maker’s own figure and is loaded heavily enough for solids to come out well above that; the answer is warmth and patience.

Streaks running one way across a fibre print. Agitation, not chemistry — see mottled development. On the Fomatone papers the Foma sheet adds a specific warning of its own: stopping development before fixing is “very important with this paper”, and neglecting it can cause non-homogeneities in the grey areas.

Marks that appear only after the print has dried. If they follow the path of a blade, they are squeegee lines and belong to the wash, not the developer.

A scum or a fine deposit in a freshly mixed tray. Hard water, most likely. The sequestrant in the concentrate is there to prevent exactly this, and less than half a per cent of it goes a long way — but it is dosed for the concentrate and not for your tap. Mixing with deionised water is the test that settles it in one session.

Experiments

Measure what the sheet publishes, then measure what it does not. The concentrate should be pH 10.5 to 11 and 1.27 g/cm³ at 20 °C. The density needs a measuring cylinder and a balance and takes two minutes; the pH needs a meter calibrated that day. Then measure the 1+7 tray solution, which no Foma document gives, and write both numbers in your notebook. You have just produced a figure this page could not give you, and a check on your own meter at the same time.

Settle the Fomatone disagreement. Foma’s developer sheet says 90 seconds minimum for Fomatone MG Classic; Foma’s Fomatone sheet says 60. Print five identical sheets from one negative at one exposure and develop them for 60, 90, 120, 180 and 240 seconds at 1+7 and 20 °C. Dry them fully — image colour on a warm-tone baryta paper changes as it dries — and compare maximum black. If 60 seconds matches 90, the developer sheet is conservative. If it is visibly weak, the paper sheet’s minimum is optimistic and the developer sheet is the one to follow.

Convert the capacity into your own sheet count, and then verify it. Mix exactly one litre at 1+7, put an identical control sheet through at the start of every batch of ten, and plot the maximum black of the controls against the number of sheets. The prediction from Foma’s area figure is a fall somewhere near 58 8 × 10 RC sheets or 29 on fibre. Whatever number you get is worth more than the maker’s, because it is for your paper, your tray and your working habits.

Find the time nobody publishes: 1+4 in a tray. Foma gives 1+4 only for a machine at 30 °C. If you want the stronger dilution at 20 °C in a dish — for a session where the tray must last a long evening — there is no published time and the course will not invent one. Make it, print a test strip series against a 1+7 print developed for the paper’s published time, and record the time at which the two match. That is how a maker’s silence gets turned into your own number.

Test the keeping the maker will not put a figure on. Fill two identical small bottles from a fresh 250 mL bottle, cap one full and leave the other half empty, and keep both in the same place. Every fortnight, mix a litre at 1+7 from each and develop one identical control sheet in each. The date at which the half-empty bottle starts to give a weaker black is the number Foma does not publish, and it will be a number about the air above the liquid rather than about the calendar. Part VIII’s aerial oxidation experiment is the same idea done in a single session and is a good rehearsal for it.

The comparison that matters most: this against D-72. Same negative, same paper, same session, the bought concentrate at 1+7 and the mixed developer at 1:4, both at their published times, and note that Kodak’s is published for 21 °C and Foma’s for 20. Part XVIII’s session sets it up properly with a third arm and a control. Record it in the formula version record — a bought product gets a line in that record too, with its dilution, the date its bottle was opened and how much paper had already been through the tray, because those are the only variables you have.

Test the maker’s own interchangeability claim. Foma’s Fomabrom and Fomaspeed sheets name Kodak Dektol, ILFORD PQ UNIVERSAL and BROMOPHEN as developers suitable for the same papers and the same neutral tone; its Fomabrom Variant sheet drops all three and names ILFORD MULTIGRADE instead. Three of those four have pages in this library — PQ UNIVERSAL, BROMOPHEN and MULTIGRADE. Print one negative on Fomabrom in FOMATOL LQN, PQ UNIVERSAL and BROMOPHEN at their own published times; then repeat it on Fomabrom Variant with MULTIGRADE in place of the other two. If Foma’s two lists are describing a real distinction, the second set will show it and the first will not.

Keep a column for the emergence time. Write down the second at which the image appears, beside the sheet number and the date the bottle was opened. Foma publishes no emergence time — ILFORD’s 35 seconds on fibre is the only such figure in this library — so the first evening’s numbers become your own baseline. It costs nothing to record, and after a month of printing it will tell you a bath is failing before a ruined print does.