ILFORD WASHAID

This is a product page, not a formula page. Every other washing aid in this library arrives as a quantity with a source beside it — ten grams of anhydrous sulfite in a litre, twenty grams of sulfite with five of bisulfite and half a gram of a sequestrant — and an account of why that quantity and not another. Nobody outside Harman knows the quantities in this bottle. What follows is what its maker publishes, which for a bath most darkrooms treat as optional is a surprising amount and is spread across six of HARMAN’s own sheets; what its maker’s safety data sheet discloses, which is three substances, one of them a trade name; a fourth substance that appears on the sheet only in the regulatory section; what all of that together still leaves unknown; and the patented open bath that does the same job with its arithmetic on the page.

HARMAN technology Limited (ILFORD Photo) — 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
Sodium sulfite (anhydrous)named on the sheet as Sodium sulphiteCAS 7757-83-7The exchanging ion. HARMAN gives no function for it, but the product's own one-sentence description says the removal of thiosulphate happens "by ion exchange", and a sulfite at the largest band on the sheet is the only thing present that can be the exchanging ion	5-10%
N-carboxymethyliminobis(ethylenenitrilo)tetra(acetic acid)CAS 67-43-6	1-5%	H319, H332, H361, H373
Empicol ESC 3	0.1367

Not disclosed. HARMAN publishes no composition for WASHAID. The safety data sheet names three components — sodium sulphite, an aminopolycarboxylic acid the sheet identifies only by its CLP name and CAS number, and something called Empicol ESC 3 — and gives each the concentration band it needs to classify a hazard, which is not an assay: section 11 records that every endpoint on the sheet was reached by calculation from those bands, and one of the three is printed as a bare four-decimal figure rather than as a range. It names no water, no alkali, no buffer and no preservative, gives no function for anything, and section 9 records the product's colour, odour, pH, density and solubility all as Not known even though the technical sheet publishes a working-solution pH and specific gravity. Section 15.1 names a fourth substance, a polysiloxane-polyether copolymer with a CAS number, that appears in no other part of the document. What is nowhere in ILFORD's literature is the sulfite concentration, the identity of the surfactant, the reason a sequestrant is present, any residual-thiosulfate figure behind the phrase "extremely low levels of retained fixer", any test method or standard those levels were measured against, and any formulation date. A reader who wants to know how much sulfite is in the tray, or to change that number and watch the wash time move with it, has to mix an open formula rather than buy this one — or measure the bought one on their own bench, which this page's experiments set out how to do.

Nearest open formula. Kodak Hypo Clearing Agent (the washing accelerator of US 2,860,978) — The two baths are built out of the same two ideas, and only one of them publishes the quantities. Kodak's patented washing accelerator is 20 g of sodium sulfite, 5 g of sodium bisulfite and 0.5 g of a tetrasodium aminopolycarboxylate sequestrant per litre of working bath; WASHAID's hazard sheet discloses a sulfite, an aminopolycarboxylic acid and a surfactant, in bands rather than in grams. So the pairing is unusually close for a product page — a sulfite doing the exchange and a chelating agent behind it, in both — and the difference is not chemistry but evidence. The patent states its molarity, its pH window of 4 to 10 with neutral called particularly useful, and residual-hypo measurements in milligrams per square inch that you can reproduce; HARMAN states a working pH of 7.00 to 7.20, a specific gravity, two times, two capacities, three keeping figures and four published sequences, and no quantity anywhere. One is a composition with almost no published performance; the other is a documented performance with no composition. They also differ in what they are sold as: Kodak's is a powder you dissolve, WASHAID is a liquid concentrate diluted 1+4, and Kodak's bath is acid-side of neutral where WASHAID's is neutral to very slightly alkaline.

Purpose

To get the fixer out of the paper faster, and more completely, than water alone will do it.

HARMAN’s own sentence is unusually informative and worth reading twice: ILFORD WASHAID “is a hypo-eliminator formulated to aid the efficient removal of the thiosulphate by-products of fixation by ion exchange.” That is a statement of mechanism on a document that gives no composition, which is the reverse of the usual bargain and is the single most useful thing on the sheet.

The number that pays for the bottle is on a different sheet. ILFORD’s instruction for washing a fibre-based print without a washing aid is 60 minutes in fresh running water. With WASHAID it becomes a 5 minute wash, 10 minutes in the aid, and a final wash of 5 or 20 minutes depending on which ILFORD sheet you are holding. Even at the long reading that is 35 minutes against 60, and at the short reading it is 20 against 60 — a third of the time and a small fraction of the water.

!A hypo-eliminator, or a hypo clearing agent?

HARMAN calls WASHAID a hypo-eliminator and then, in the same sentence, describes ion exchange. Those are two different things and the course keeps them apart, because confusing them has damaged prints.

A true hypo eliminator destroys thiosulfate chemically. Kodak’s HE-1 is hydrogen peroxide and ammonia, and it oxidises the thiosulfate that is there. It is fast, it is aggressive, and the same 1949 handbook that prints it warns about what it does to the print.

A hypo clearing agent destroys nothing. It floods the emulsion and the paper fibres with a small, freely soluble anion that displaces the thiosulfate off the sites it is clinging to, so that ordinary water can then carry it away. Nothing is oxidised, nothing is broken down, and the thiosulfate leaves the print in the wash rather than in the tray.

By its own description of its own mechanism, WASHAID is the second kind. The word on the sheet is the first kind. The course reads the mechanism clause as the operative statement and the noun as loose trade usage, and marks that reading as an inference under Rule 7 rather than as a HARMAN statement. Nothing practical hangs on it except this: do not treat WASHAID as a licence to shorten the fixing, and do not treat it as something that will rescue a print that was fixed badly.

Recommended uses

Fibre-based paper, 10 minutes at 1+4, inside a published sequence. This is what the product is for. ILFORD says so twice — “particularly useful in speeding up the washing of fibre based papers” and “designed to be used with the ILFORD optimum permanence sequences” — and every one of the four sequences it prints is a fibre-paper sequence.

Film, 2 to 3 minutes at 1+4. The sundries sheet’s standard table gives film its own column: a 1 minute first wash, 2 to 3 minutes in the aid, a 5 minute final wash. This is a much smaller saving than the paper case, because film was never a 60-minute wash to begin with.

After a hardening fixer. ILFORD names this twice as well, on the sundries sheet — “particularly useful if a hardening fixer has been used” — and on the paper developers sheet, where the reason is given: hardened prints take longer to wash. A hardened gelatin swells less, and what does not swell does not exchange.

With selenium toning, as the toner’s diluent. The most interesting sequence on the sheet. Instead of water, the selenium toner is diluted with working strength WASHAID, the print goes straight from a one-minute fix into the toner with no wash between, and the toning bath and the clearing bath do their work at the same time. Kodak arrived at the same arrangement independently for its own toner, which is recorded on the Hypo Clearing Agent page, and HARMAN’s own selenium toner sheet points fibre printers at “the ILFORD optimum permanence wash sequence” as the alternative to a 30 minute wash, without naming WASHAID in that sentence. For the toner itself the course teaches Kodak Limited’s 1949 selenium toner, which publishes its quantities.

Where water is short. ILFORD wrote a whole separate sheet for that reader in 2015, and its answer for fibre paper is this product. Under a hosepipe ban or a meter, a 20-minute total sequence against a 60-minute running wash is not a convenience, it is the difference between printing and not.

Where the print is going to be kept. The phrase ILFORD uses is “optimum permanence… perhaps for archival storage of prints”, and it is careful to say first that the standard recommendations “will give excellent print permanence for all commercial needs”. The product is for the case above commercial needs. Part XII’s archival sequence is where the course sets out what that case is.

When another formula is preferable

• When you want to understand a washing aid rather than buy one, mix Kodak’s Hypo Clearing Agent from the patent that describes it. It is a sulfite bath with a sequestrant behind it, published with quantities, a pH window and measured residual-hypo figures, and it is the comparison this page is built around.
• When the work is albumen, salted paper or another printing-out process, the 1 per cent sodium sulfite washing aid is the bath the conservation literature specifies for exactly those papers, with its own exhaustion figure and its own place in a sequence written for them.
• When the paper is resin-coated, nothing. ILFORD’s own scope for WASHAID is films and fibre papers; RC paper is not in it, and the RC wash on the same maker’s fixer sheet is 2 minutes, or 30 seconds vigorously when speed matters. A washing aid cannot usefully accelerate a two-minute wash, and the sheet on reducing water use warns separately against over-washing RC paper at all.
• When the print was over-fixed, or the fixer was over-used, no washing aid of any kind. ILFORD prints the warning on the sheet in bold terms — “be careful not to exceed the capacity of the fixer and not to extend the fixing time as both of these make washing more difficult” — and the reason is chemical rather than procedural. Part XI has it in full.
• When you want the hypo destroyed rather than displaced, HE-1 is the formula, and the course publishes it as a historical study with its warnings attached rather than as a recommendation.
• When what you actually need is a measurement, no bath at all: run HT-2 on the prints you are already making and find out whether your present wash is failing before you buy something to fix it. The residual hypo and silver SOP is the procedure.

What the maker publishes

A great deal, and — unusually — a working-solution pH rather than a concentrate pH.

One dilution, and only one. 1+4, for film and for paper alike. There is no second dilution for economy and no different strength for film. Whatever else is uncertain here, the strength you use it at is not.

The working solution’s pH and specific gravity. pH 7.00 to 7.20 and SG 1.020 at 20 °C, printed for ILFORD WASHAID 1+4 — the diluted bath, not the bottle. That is the opposite of what the same sheet does for ILFOSTOP, where the pH given is the concentrate’s and the working figure is withheld. Here the figure you can actually check on your own bench is the one that is published, and ILFORD prints the caveat that goes with it: the figures were obtained under carefully controlled laboratory conditions, may differ slightly from a user’s own measurements, and the right use of them is to make your own control measurement and compare later ones against it.

A temperature range rather than a temperature. 18 to 24 °C, with the paper sheets extending it to the whole sequence including the wash water.

Two times, for two materials. 10 minutes for fibre paper and 2 to 3 minutes for film, both at 20 °C.

Two capacities, and the same number twice. Per litre of working solution: 2 m² (11 ft²) or 40 films of 135/36 for film, and 40 sheets of 20.3 × 25.4 cm for fibre paper. Forty 8 × 10 inch sheets is 2.06 m², so the paper count and the film area are one capacity expressed twice — that arithmetic is the course’s, on ILFORD’s own printed figures.

What a bottle makes. 1 litre of concentrate, diluted 1+4, makes 5 litres of working solution: 200 sheets of 8 × 10 fibre paper or 200 films. Both follow exactly from the per-litre figure times five, which is not true of every availability paragraph ILFORD prints.

Three keeping figures. Four years for the concentrate in a full airtight bottle, six months once the bottle is half full and tightly capped, seven working days at working strength.

The mixing method, in the order ILFORD does it. Work out how much the session needs, at least enough to fill the dish about half full. Measure the concentrate with the smallest cylinder that will hold it. Add it to the mixing vessel, using a large measuring jug so the total is checked as you go. Measure the dilution water with hot and cold to arrive at 20 °C. Rinse the concentrate cylinder out into the mixing vessel with some of that water, then add the rest and stir. The mixing SOP draws the general lesson from this paragraph.

Four published sequences, which is three more than most products get.

	Fix	First wash	WASHAID 1+4	Final wash
Standard, FB paper	as the fixer sheet gives it	5 min	10 min	20 min
Standard, film	as the fixer sheet gives it	1 min	2–3 min	5 min
Optimum permanence, FB paper	RAPID FIXER or HYPAM 1+4, 1 min	5 min	10 min	5 min
Optimum permanence with selenium	RAPID FIXER 1+4, 1 min, then tone in selenium diluted with working-strength WASHAID	—	10 min	30 min

And one instruction that is worth more than the tables. “Be careful not to exceed the capacity of the fixer and not to extend the fixing time as both of these make washing more difficult.” It appears on the sundries sheet and on every fibre paper sheet in the corpus. A washing aid is downstream of the fixer, and the sentence is HARMAN telling you that it cannot repair what happens upstream.

!Five minutes or twenty? HARMAN's sheets do not agree

The final wash after WASHAID is given as 5 minutes on three documents and 20 minutes on two, and one sheet prints both.

The sundries sheet’s standard processing sequence table gives fibre paper 5 / 10 / 20. Its optimum permanence sequence, half a column away, gives 5 / 10 / 5, after a one-minute fix. The RAPID FIXER and HYPAM sheets give 5 / 10 / 5 as a straight replacement for the 60-minute wash, with no fixing condition stated in that paragraph. The paper developers sheet gives at least 5 minutes before and 20 minutes after. The 2015 sheet on reducing water use gives 5 / 10 / 5 after a one-minute fix.

The obvious resolution — that the short final wash belongs with the short fix — does not survive checking. RAPID FIXER’s own table gives one minute as the ordinary fixing time for fibre paper at 1+4, so the “very short fixing time” the optimum permanence section credits is the standard one.

What the course does about it. It reads the 20-minute figure as the one that covers every fixing condition a reader might actually be in — a hardening fixer, a 1+9 dilution at two minutes, a bath that has already taken thirty sheets — and the 5-minute figure as the one HARMAN measured on a one-minute non-hardening fix at 1+4 with a fresh bath and every solution inside 18 to 24 °C. That is an inference of the course’s, marked as one under Rule 7, and HARMAN offers no reconciliation. The practical rule needs no inference at all: a longer final wash is never wrong, and if you cannot say which of HARMAN’s conditions you were in, wash for twenty minutes. Better still, stop guessing and run HT-2 on a test print.

What is not disclosed

The sulfite concentration, which is the whole of the formula for a bath whose working ingredient is a sulfite. The band on the hazard sheet is 5 to 10 per cent of the concentrate, a factor of two wide, and it is a classification band rather than an assay.

What the sequestrant is for. The sheet names an aminopolycarboxylic acid, bands it, classifies it and stops. No function is stated, on that document or on any other in ILFORD’s literature.

What Empicol ESC 3 is. A trade name, with no CAS number and no EC number beside it — which is what a trade name looks like on a composition table when the supplier does not want the substance identified. The course does not know what it is and will not guess.

Everything measurable in section 9. Appearance is “Liquid”. Colour, odour, pH, density, relative density, solubility, viscosity, decomposition temperature: all Not known. The company that publishes pH 7.00 to 7.20 and a specific gravity of 1.020 in its technical sheet records both as unknown in its hazard sheet, which tells you something about how these documents are produced.

Any number behind “extremely low levels”. The optimum permanence section claims that its sequences “give extremely low levels of retained fixer and silver compounds”. There is no figure, no unit, no test method and no standard named. That is the claim the whole product rests on and it is unquantified in every ILFORD document in this corpus. Part XII’s wash testing lab exists because of sentences like that one.

A fourth substance, on the sheet and in one section only. Section 15.1, the UK REACH Annex XVII restrictions line, reads: “Reproductive toxicants: Category 1 B (67-43-6), POLY[DIMETHYLSILOXANE-CO-METHYL(3-HYDROXYPROPYL)SILOXANE]-GRAFT-POLY(ETHYLENE GLYCOL) METHYL ETHER (117272-76-1)”. That polymer, with its own CAS number, appears nowhere else on the document — not in section 3.2, not in section 9, not in section 16. The course records it as printed and does not treat it as a disclosure of composition, because a restrictions list is not a composition table and the sheet says nothing about why the entry is there. The same line also gives 67-43-6 a reproductive toxicity category of 1B, where section 3.2 of the same sheet classifies it Repr. 2. Both statements are HARMAN’s, on one document, two pages apart.

!Why the three bands cannot be added up

There are three numbers in the composition table and the temptation to treat them as an assay is the reason this page kind exists. Do the arithmetic once and it goes away.

Sodium sulphite is banded at 5–10 %, the aminopolycarboxylic acid at 1–5 %, and Empicol ESC 3 is given as 0.1367 in a column headed %W/W. Taken at their lower limits the three named substances account for about 6 per cent of the bottle; at their upper limits, about 15 per cent. So between 85 and 94 per cent of the concentrate is not named by any substance on the sheet — most of it water, on any sensible reading. Both totals are the course’s arithmetic on HARMAN’s own printed figures, and neither is a composition.

Worse for the reconstructionist: the sulfite band is a factor of two wide, and the whole behaviour of an ion-exchange bath is set by how much exchanging ion is in it. A working bath built from a 5 per cent concentrate holds half the sulfite of one built from a 10 per cent concentrate, and those two baths would clear a fibre print at measurably different rates. The band is not a manufacturing tolerance. It is a band chosen so that the mixture’s classification can be calculated conservatively, and section 11 confirms that calculation is exactly what happened — every endpoint on the sheet reads “Calculation method”.

And notice what the third band does to the whole idea. 0.1367 is not a band at all: it is a single figure printed to four decimal places, a precision no hazard classification could possibly require, sitting in the same column as two ranges. The same house style appears on HYPAM’s sheet, where two of three components are given to four decimals. Whatever process generates these tables is not one whose numbers can be read as a recipe.

Read as the hazard document it is, this table is evidence, and this page uses it as evidence. Reassembled into a recipe it would be a fabrication with citations attached, and no amount of care about the arithmetic would make it anything else.

Disclosed components

Three, in the order the safety data sheet prints them, with the concentration against each being the band the sheet states and not a quantity.

Sodium sulphite, CAS 7757-83-7, EC 231-821-4, 5–10 %. The largest disclosed component and, on the sheet’s own numbers, the only one present in a quantity that could do the work. It is classified Not classified, with no hazard statement and no pictogram against it — which is worth pausing on, because sulfite is not an innocuous substance in every context, and the context in which it is not is an acid one. Three properties matter here and its encyclopaedia page has the rest. It is small, doubly charged and freely soluble, which is exactly the profile of a good exchanging anion. It is a reducing agent, which is why it also appears in every developer in this library as a preservative and why an oxidiser must never meet it. And acid liberates sulfur dioxide from it, which is the one genuine hazard of this bath and belongs to the darkroom rather than to the bottle.

N-carboxymethyliminobis(ethylenenitrilo)tetra(acetic acid), CAS 67-43-6, EC 200-652-8, 1–5 %. That mouthful is the CLP Annex VI style of name, and the registry number resolves it: CAS 67-43-6 is diethylenetriaminepentaacetic acid, known as pentetic acid or DTPA, C₁₄H₂₃N₃O₁₀, molecular weight 393.35. It is an aminopolycarboxylic acid — the same structural family as EDTA, with five carboxylate arms and three nitrogens instead of four and two, and correspondingly a stronger and broader chelator. The course has no encyclopaedia page for it, because outside industrial water treatment it is not a photographic chemical. It is the component that carries such classification as this product’s components have: Eye Irrit. 2 (H319), Acute Tox. 4 (H332), Repr. 2 (H361) and STOT RE 2 (H373), with pictograms GHS07 and GHS08. Its own aggregated picture across 530 ECHA notifications is broadly the same but harsher on one point — signal word Danger, H319 in 98.7 per cent of reports, H332 in 71.7, H373 in 51.5, and the reproductive statement split between H360D in 46.2 per cent and the milder H361 in 34.3, with 7 reports of 530 finding it meets no GHS criterion at all. HARMAN chose the milder of the two reproductive classifications in section 3.2 and the harsher category in section 15.1, and the course notes both without resolving them.

What it is doing there, HARMAN does not say. A reading is offered under The mechanism below and it is marked there as an inference.

Empicol ESC 3, no CAS number, no EC number, printed as 0.1367 in the %W/W column. This is a trade name and nothing else. The sheet gives it no registry number, no EC number, no hazard statement, no pictogram and no function, and classifies it as Not classified. The course therefore cannot say what it is, and will not reason from the name to a substance: a manufacturer’s product designation is not a chemical identity, and a page that inferred one would be reconstructing a formulation by the back door. What can be said is what the sheet prints — that it is much the smallest of the three, and that its figure is a single number to four decimal places rather than a band, which is a peculiarity of the document rather than a fact about the product.

And a fourth substance, in the regulatory section and nowhere else. Section 15.1 names a polysiloxane-polyether graft copolymer, CAS 117272-76-1, on the Annex XVII restrictions line. It is not in the composition table, so it is not in the table above and it is not a disclosed component of this product as far as this course is concerned. It is recorded here because it is printed on the document, and because it is the clearest possible illustration of what these tables are and are not: a safety data sheet lists what drives a classification, not what is in the bottle.

Behaviour

Ten minutes for paper, two to three for film, and the times are not a slope. Unlike a development time, these are not points on a curve where a little more gives a little more. They are the times at which HARMAN judges the exchange to have gone as far as it usefully goes, and the sheet offers no figures for going further. The published temperature band, 18 to 24 °C, is wider than ILFORD allows any of its developers, which is what a diffusion-limited exchange looks like in an instruction.

It saves a lot of time on fibre paper and very little on film. Sixty minutes down to twenty or thirty-five for a fibre print. For film the standard sequence is 1 / 2–3 / 5 — the whole thing takes under ten minutes with or without it, and ILFORD’s own minimum-water sheet does not use WASHAID for film at all, offering three fill-and-invert cycles instead. That is the honest scale of the benefit: this is a paper product that also works on film.

Its capacity and the fixer’s are the same number. Forty 8 × 10 fibre sheets per litre for the WASHAID, forty per litre for RAPID FIXER at 1+4. A darkroom that mixes a litre of each and works through both in step will exhaust them together, which is a convenience the sheets do not point out and the course does.

Seven working days is the other limit, and it is independent of the count. A tray that has taken ten prints in a week is finished on the calendar even though it is a quarter of the way through its capacity. HARMAN gives no reason. A sulfite in an open tray oxidises slowly to sulfate in air, and a sulfate is not an exchanging ion in the same way; that is the obvious candidate for the reason and it is an inference of the course’s, not a HARMAN statement.

It cannot rescue a badly fixed print, and the sheet says so before you ask. Exceeding the fixer’s capacity or extending the fixing time both make washing harder, which is counter-intuitive until you know why: a tired fixer leaves the less soluble silver-thiosulfate complexes in the paper rather than the freely soluble ones, and no amount of sulfite will exchange those out. Part XI works it through, and the Hypo Clearing Agent page quotes the patent that demonstrated it.

The first wash before it is not optional. Every ILFORD sequence puts 5 minutes of running water in front of the aid for paper and 1 minute for film. The conservation literature gives the reason that ILFORD does not: a print carried straight from the fixer into the clearing bath overloads the exchange with the fixer it is still dripping, and the bath spends its capacity on liquid that plain water would have removed for nothing. The 1 per cent sulfite page carries that argument with its source.

Neutral, and staying neutral. pH 7.00 to 7.20 in the working bath is the flattest figure in this formulary. It means the bath does not stop development, does not fix, does not tone and does not attack anything — it exchanges, and nothing else.

Image characteristics

A washing aid has none, and saying so plainly is worth a paragraph. It dissolves no silver halide, removes no silver, changes no image tone, alters no contrast and makes no print look different coming off the drying rack. Every tonal property of the finished print was decided in the trays before it.

What it changes is the print in twenty years’ time. Residual thiosulfate in a fibre base is the classic slow poison of a silver-gelatin print: it attacks the image silver, and the result is the yellow-brown highlight staining and general fading that Part XII’s permanence page sets out. WASHAID’s contribution is entirely to that future, which is why HARMAN’s claim for it is a claim about “optimum permanence” and not about appearance, and why the claim is untestable in the session that makes the print.

It has one documented indirect effect on image colour, and it is not its own. In the selenium sequence the toner is diluted with working-strength WASHAID instead of water, so the clearing bath becomes the toner’s carrier. Whether that alters the toned colour, HARMAN does not say and this page will not assert. What is stated is the sequence, and that the final wash after it is 30 minutes rather than 5.

The safety data sheet records the product’s own colour as Not known, and the course has found no ILFORD statement anywhere that the bath stains anything. There is no indicator dye here, and no reported residue.

The mechanism

Ion exchange, which is HARMAN’s own word for it. Thiosulfate ions are not merely dissolved in the water inside a wet print; a large fraction of them are held on the gelatin and, in a fibre paper, on the cellulose of the base. Held ions come off slowly, and a running wash spends most of its hour waiting for them. Flood the print with a large excess of a different small anion and the held sites give up their thiosulfate to it until a new equilibrium is reached; the displaced thiosulfate is then free in solution and an ordinary wash removes it in minutes. That is the whole trick, and Part XII’s physics of washing gives the diffusion argument behind it.

Why a sulfite is the ion chosen. It is small, it carries two negative charges, it is very soluble, it is cheap, and — critically — a trace of it left behind in the paper does no harm. Several of those are true of other anions; the combination is what makes sulfite the standard. Henn and Crabtree’s patent, which is the primary document for this entire class of bath, tested the alternatives and published the comparison, and the Hypo Clearing Agent page carries it.

Why the sequestrant is probably there, marked as an inference. DTPA is a chelating agent. Two jobs in a wash aid would suit it, and both readings are the course’s, not HARMAN’s: it would bind the calcium, magnesium and iron of hard tap water, which otherwise precipitate in an alkaline sulfite bath and can leave deposits on a fibre surface; and trace iron and copper catalyse the aerial oxidation of sulfite, so a chelator that locks those metals up extends the working life of the very ion doing the work. The strong evidence that a sequestrant belongs in a bath of this kind is not HARMAN’s at all — it is Kodak’s, whose patented washing accelerator carries half a gram per litre of the tetrasodium salt of EDTA alongside its sulfite, published with the quantity. That two makers independently put an aminopolycarboxylate in a sulfite wash aid is a fact; why HARMAN put this one in is not stated anywhere, and neither reading above is an identification of its function.

Why the surfactant is probably there, marked as an inference and left short. A bath that has to penetrate a fibre paper base in ten minutes is a bath with a wetting problem, and a small addition at a tenth of a per cent is the order of magnitude at which such additions are made. The course goes no further than that, because Empicol ESC 3 is a trade name and the sheet gives it no identity to reason from.

Why a hardening fixer makes it matter more. A hardened gelatin is cross-linked, swells less, and lets ions in and out more slowly. Everything above depends on the exchanging ion reaching the held thiosulfate, so hardening slows the exchange as surely as it slows the wash — which is why ILFORD recommends the aid for hardened prints, and why the paper sheets tell you not to harden at all when permanence is the aim. Both instructions are HARMAN’s, and they are not in conflict: one is for the print you have, the other for the print you are about to make.

Why “extremely low levels” is a claim and not a measurement. Nothing in ILFORD’s literature says how low, against what standard, or measured how. The course’s answer is not to argue with the claim but to test it, and the wash testing lab is where a reader does that with HT-2 on their own prints.

The nearest open formula

Kodak’s Hypo Clearing Agent, the washing accelerator of Henn and Crabtree’s 1954 patent, and the comparison is unusually close.

That bath is 20 g of sodium sulfite, 5 g of sodium bisulfite and 0.5 g of a tetrasodium aminopolycarboxylate sequestrant per litre of working solution, published in a patent that also gives a pH window, a mechanism in three parts and residual-hypo measurements in milligrams per square inch. WASHAID’s hazard sheet discloses a sulfite, an aminopolycarboxylic acid and a surfactant. This is not a claim that they are the same bath — the bisulfite, the strengths, the salt forms and the surfactant are all different or unknown — but it is as near as a product page in this library gets to its open counterpart, and the difference between them is evidence rather than chemistry.

	Kodak’s Hypo Clearing Agent	ILFORD WASHAID
Composition	20 g sulfite, 5 g bisulfite, 0.5 g sequestrant per litre, from the patent	A sulfite at 5–10 %, an aminopolycarboxylic acid at 1–5 %, a named surfactant at 0.1367, of a concentrate; amounts not published
Exchanging ion	Sodium sulfite, quantity known	Sodium sulphite, quantity banded
Sequestrant	The tetrasodium salt of EDTA, 0.5 g/L, in the patent’s claim	DTPA, banded, function not stated
Surfactant	None	Empicol ESC 3, not identified
Form	Powder, dissolved to volume	Liquid concentrate at 1+4
Published pH	A window of 4 to 10, with neutral called particularly useful	7.00–7.20 for the working solution, measured
Published time	1 to 2 minutes for film, 2 to 3 for fibre paper, on Kodak’s own sheets	10 minutes for fibre paper, 2 to 3 for film
Published capacity	Kodak’s sheets give sheets per litre with and without a pre-rinse	40 films or 40 fibre sheets per litre
Published performance	Residual hypo and residual silver in mg per square inch, measured, in the patent	“Extremely low levels”, unquantified
Keeping	Kodak publishes stock and working-solution figures	4 years sealed, 6 months half full, 7 working days in use
What you can change	The sulfite concentration, and therefore the exchange	The time and the temperature

The last row is the argument. Buying the concentrate gets you a documented sequence, a keeping life, a working pH you can verify and two capacities, from a bath whose one important number is unknowable. Mixing the patent’s bath gets you that number, and a set of published measurements to compare your own against. Part XII’s wash testing lab is where a reader turns one into the other, by measuring on their own bench what HARMAN’s documents do not give them.

For albumen, salted paper and the other printing-out processes, the nearer open bath is the 1 per cent sodium sulfite washing aid, which the conservation literature specifies for exactly those papers and which carries its own exhaustion figure.

Safety

Level A, and this one is easy, because HARMAN classifies the product as nothing at all.

Section 2.1 reads “Not classified as dangerous for supply/use” under the GB CLP Regulation. Section 2.2 gives hazard pictogram None, signal word None, hazard statement None. Section 2.3, other hazards, none known. Section 11 records every toxicological endpoint as Not classified, reached by calculation. This is the shortest classification of any product in this formulary — shorter than ILFOSTOP’s single H319 — and it sits comfortably inside Level A on the classification rubric.

Why an unclassified product still carries a Repr. 2 component. The DTPA is classified Repr. 2, H361, at 1–5 % of the concentrate, and the mixture is not classified for reproductive toxicity at all. That is not an oversight. A category 2 reproductive toxicant carries its classification into a mixture only at or above a concentration limit, and HARMAN’s own classification of the mixture therefore says that its real figure for this component is below that limit. Since the limit is lower than the top of the printed band, the sheet’s two statements together constrain the true concentration more tightly than the band does on its own — which is an inference of the course’s, marked under Rule 7, and still not a quantity. The relationship between a component’s classification and a product’s is the whole subject of the GHS and CLP page, and this sheet is a clean worked example of it.

Personal protection, as the sheet specifies it. Eye protection with side protection to EN ISO 16321-1. Skin protection: not normally required. Respiratory protection: normally not necessary. Adequate ventilation. Precautionary statements P102, P280, P302+P352, P305+P351+P338 and P501 are printed even though there is no hazard statement to attach them to.

Why the course still asks for gloves. Not because of the product. Because the bath sits in a sequence between a fixer and a wash, because the hands that move prints between those trays are the same hands, and because the discipline that keeps a fixer out of a developer is a habit rather than a decision. The glove selection page and the PPE SOP govern.

First aid, in the sheet’s own words. Inhalation: remove to fresh air if breathing is difficult. Skin: wash with water. Eyes: flush for at least 15 minutes. Ingestion: wash out the mouth with water. Symptoms: none anticipated, treat symptomatically. The first-aid page has the course’s fuller procedure and the eyewash SOP has the technique.

⚠The hazard that is not in this product's classification

Nothing on WASHAID’s safety data sheet mentions sulfur dioxide, and by the logic of that document nothing needs to: the gas is not a property of the bath, it is a property of acid meeting sulfite.

This bath is 5 to 10 per cent sodium sulphite in the bottle, and it lives in a room where the tray before it is an acid fixer and the tray before that may be an acid stop bath. Pour a spent WASHAID into a waste bottle that already holds spent fixer and you have made the reaction on purpose. The incompatibilities page has it, with limits that are among the tightest gas limits in this course.

The control is procedural rather than chemical: keep the baths in the order they belong in, never pour one waste stream into another, and do not let a tray over-concentrate by standing.

Note also what an unclassified product costs you here. A sheet with no pictogram on it invites the assumption that nothing in the bottle matters. The sulfite matters — not on its own, and not in the tray, but in the bottle you are about to pour it into.

Storage

The concentrate, capped, upright, at ambient temperature and out of reach of children, which is the safety data sheet’s own storage instruction and the only one it gives. Its storage life entry reads stable under normal conditions and its incompatible materials entry reads none known.

ILFORD’s own figures are four years and six months. Four years in a full airtight bottle; six months once the bottle is half full and tightly capped. The clock is started by the air space, not by the seal — which for a sulfite is exactly the right way round, because what shortens the life is oxygen. Note that these are shorter than ILFOSTOP’s five years and twelve months, from the same maker in the same sheet, which is what you would expect of a reducing agent against an acid.

Seven working days at working strength, and the count runs at the same time: 40 fibre sheets per litre, whichever arrives first.

Buy for the darkroom you have. A 1 litre bottle makes 5 litres of working solution and will clear 200 fibre prints. If a year’s printing is thirty fibre prints, the six-month figure will run out long before the bottle does, and a smaller bottle bought twice is cheaper than a large one thrown away.

Label everything, with the product, the dilution and the date mixed, using the labelling SOP. This bath is water-clear, neutral, odourless and sitting between two other water-clear trays. An unlabelled or undated container is the failure that costs a session, and this is the product least likely to announce its own identity.

Incompatibilities

Acid, in every form, because of the gas. Fixer, stop bath, and any acid in a waste container. Acid liberates sulfur dioxide from a sulfite, and the arrangement that does it fastest is a waste bottle holding both. In the process sequence the transfer is intended and controlled — a small carried-over volume, and a wash between — and that is a different thing from mixing the two in a bottle. The incompatibilities page governs.

Oxidisers, because sodium sulphite is a reducing agent. Peroxide, persulfate, permanganate, dichromate, hypochlorite: none of these belong anywhere near this tray or its waste. That includes HE-1, the peroxide hypo eliminator, which is a different approach to the same problem and must never be combined with this one.

Carrying the bath backwards into the fixer. A sulfite carried back on tongs into an acid fixer does two unwanted things at once — it makes gas, and it dilutes and shifts a bath whose pH window matters. ILFORD’s general instruction on the same sheet is to wash all utensils, measuring and mixing vessels thoroughly after use and to use dedicated equipment wherever possible. The two-bath fixing rotation SOP is where the tray discipline lives.

Hardener, in the fixer before it. Not an incompatibility in the chemical sense but in the procedural one, and HARMAN states it plainly on every fibre paper sheet: for optimum permanence, do not add a hardener to the fixer. Hardened gelatin exchanges more slowly and washes more slowly, which is the opposite of what the sequence is for.

✕What sections 7.2 and 10.5 say, and why they are not the last word

Section 7.2 gives incompatible materials as “None known” and section 10.5 gives them as “Not known”. Read literally, that says a 5 to 10 per cent sulfite solution has no chemical incompatibilities, which is false in a room where the previous tray is an acid fixer.

A safety data sheet answers a narrow question — what makes this product itself unstable or dangerous, in its own container — and it answers it well. It is not a compatibility chart for a process, and this sheet is the mildest in the formulary precisely because the product on its own is mild. The course’s incompatibilities page governs here.

Waste

Bottled separately, and never into the fixer bottle. ILFORD’s own instruction to domestic users is that chemicals should be bottled separately and appropriately labelled; its instruction to business users is stronger — different waste chemicals should not be mixed, and should be kept in separate, appropriately labelled containers. For this bath the reason is immediate: it is a sulfite and the fixer is an acid.

What the safety data sheet says. Dispose at a suitable refuse site, and — remarkably — “no special precautions are required for this product”. Section 12 records low toxicity to aquatic invertebrates, fish and algae, other adverse effects none known, not classified as a marine pollutant. Section 6 asks that large quantities are not released into surface water or drains, and that spillages are adsorbed onto sand, earth or any suitable adsorbent.

But the used bath is not the product, and this is the point the sheet cannot make. Everything WASHAID is for consists of taking thiosulfate — and with it silver-thiosulfate complexes — out of prints and holding them in solution. A litre that has cleared forty fibre prints is a silver-bearing waste stream, and the sheet’s “no special precautions” was written about a sealed bottle of concentrate, not about that tray. Part XII’s silver recovery and waste streams sets out which streams carry silver and what to do with them, and the silver-bearing waste SOP is the procedure. Treating spent washing-aid as ordinary drain waste on the strength of section 13 is the most likely way a careful reader of this sheet gets it wrong.

ILFORD’s own route for a United Kingdom household is the chemical cupboard at a Household Waste and Recycling Centre, with each waste stream bottled apart from the others and labelled for what it is; the company adds that a small number of local authorities will collect instead, on request.

The disposal caveat governs and local regulation decides. The general chemical waste SOP gives the procedure this course follows.

Troubleshooting

A print that tests positive for residual hypo after the full sequence. Do not lengthen the WASHAID step first — check the fixer. An over-used or over-long fix leaves complexes no clearing bath will exchange out, and ILFORD’s warning about fixer capacity is on the same sheet as the sequence. Residual thiosulfate is the entry and Part XI’s break/fix page walks the diagnosis.

Yellowing highlights on a print some months old. The failure this product exists to prevent, and by the time it shows the cause is history. Yellow-brown highlight stain from residual silver and residual silver and yellow staining are the entries; the fix is upstream, in the fixing and in the sequence.

A five-minute final wash that was meant to be twenty. The commonest way to get this wrong is to take the sequence from one ILFORD sheet and the fixing conditions from another. If you cannot say which of HARMAN’s conditions you were in, wash for twenty minutes and test.

A bath used past its date or its count. Seven working days, forty fibre sheets to the litre, whichever comes first. There is no indicator here and no smell: a spent WASHAID looks exactly like a fresh one, which is the argument for the label rather than for the eye.

A bath mixed at the wrong strength. 1+4 is 200 mL of concentrate in a litre of working solution, not 250 and not 100. A misread dilution ratio is the entry, and the mixing-from-a-stock SOP is the procedure that prevents it.

Prints that dry with a bloom or a deposit. Suspect the water before the bath — a hard supply, or a tray topped up rather than remade. ILFORD’s separate note that some non-ILFORD papers yellow on prolonged washing and can bloom over the blacks belongs beside this one.

Uneven clearing across a large sheet. The sequences all say intermittent agitation, and a sheet left floating rather than pushed under is a sheet whose back never met the bath. Mottled development is the nearest entry for the mechanism, and the answer here is the same one.

A film wash that leaves marks. Not this bath. Drying marks are a wetting problem rather than a washing one, and ILFORD’s own answer to them is on the same sundries sheet: a final rinse in its non-ionic wetting agent ILFOTOL at 1+200, a product the course has no page for because HARMAN publishes no composition for that one either.

Experiments

Measure the pH of your working bath against ILFORD’s published figure. Mix a litre at 1+4, calibrate a meter that day using the calibration SOP, and compare against 7.00 to 7.20. This is the rare case where the maker publishes the working figure and invites you to check it. Record it, and compare every later bath against your own first measurement rather than against the sheet.

Measure the specific gravity too. A hydrometer covering 1.000 to 1.200 reads 1.020 on a fresh 1+4 bath if the bottle is what it says it is. It is a thirty-second check that catches a misread dilution before a print does.

Titrate the bath for sulfite, and find the number HARMAN withholds. A standard iodometric titration on a measured volume of working solution gives the total sulfite in grams per litre. Scale it by five and you have the concentrate’s sulfite content — not read off a hazard sheet, but measured on your own bench, which is an entirely different kind of knowledge and an entirely legitimate one. Then ask whether your figure falls inside the 5 to 10 per cent band the sheet prints. If it does, you have shown the band honest; if it does not, you have found something worth writing down. Either way, record it in the formula version record — a bought product gets a line in that record too, with its dilution, its bottle date and its batch.

Test the claim the sheet does not quantify. Two matched fibre prints from one negative, fixed identically. One gets the plain 60 minute wash; the other gets 5 / 10 / 5. Run HT-2 on both, following the residual hypo and silver SOP, and read the stains against each other. Part XII’s wash testing lab is the full protocol.

Settle the five-versus-twenty question on your own paper. Three prints, all fixed one minute in fresh RAPID FIXER at 1+4: 5 / 10 / 5, 5 / 10 / 20, and 5 / 10 / 60. HT-2 on all three. If the first two are indistinguishable you have your answer for your water, your paper and your tray; if they are not, you have found the condition HARMAN’s shorter sequence assumes and you did not have.

Run the capacity down against ILFORD’s figure. Forty 8 × 10 fibre sheets to the litre. Process them in tens, testing one print from each batch with HT-2, and find out where your curve turns. Your carryover, your paper weight and your first-wash discipline all move that number, and none of them are HARMAN’s.

This against the patent’s own bath. Mix a litre of Kodak’s washing accelerator to the published quantities, run matched prints through each, and test both with HT-2. If they are indistinguishable, the product’s advantage is entirely in the convenience, the keeping and the published sequences — which is a defensible thing to buy, and worth knowing that it is the whole of what you are buying.

Measure the water saving, since that is half of what the sheet claims. A bucket under the wash outlet and a stopwatch, for the 60 minute wash and for the 20 minute sequence. Convert to litres per print. In a drought year that number is the argument, and nobody else’s number will do for your tap.

Test whether the first wash earns its five minutes. Two prints, one straight from the fixer into the WASHAID, one after ILFORD’s 5 minute rinse, both then given identical final washes and tested with HT-2. The conservation argument says the pre-rinse protects the exchange capacity; this is the bench test of it, and it is one of the few claims on this page that a single evening will settle.