Capstone Stage 5: The Toned Print and the Alternative-Process Print

Purpose

To discharge requirements 9 and 10 — at least one toned image and at least one made in an alternative process — and to force the judgement the capstone exists to make you make: laid beside the silver prints, does a treated print belong to the same body of work, or is it a different statement about the same subject?

Both answers are acceptable if they are argued. An unexamined inclusion is not.

Nothing on this page teaches toning or an alternative process. Part XX owns the toning chemistry and the compensation measurement; Parts XXI to XXV own the processes and the coating. What this stage adds is the decision, the record, and the requirement that both treated prints be finished to the same standard as the silver ones.

Learning objectives

By the end of this stage you will be able to:

• choose an image to tone from what you want the image colour, the deep tones and the upper scale to do, and say what the chosen mechanism will cost in density, in hazard and in waste;
• print for a toner, applying the compensation you measured in Part XX, with a matched untoned control from the same map in the same session;
• run a toning session to a written procedure with the bath separation planned as a room layout;
• choose and declare a negative route for an alternative process from published density ranges rather than from trial;
• choose a process from measured fields, with cost per sheet and hazard as explicit criteria;
• write a chemistry statement for each treated print naming what the image is made of now and by what reaction;
• decide whether each treated print belongs in the body of work, and argue it either way.

Prerequisites

Stage 4, with the silver set finished and the two or three candidates for treatment identified.

From Part XX, how toning changes the image, the toned print — which owns the compensation measurement this stage applies — and toning, permanence and archival evidence, which owns the four-part permanence statement. From Part XXI, negatives and papers for the alternative processes, which owns the density-range table and the three negative routes. From Part XXV, the process comparison atlas. From Part XXIV, clearing, toning and the permanence of iron-silver prints.

SOPs executed here: the UV unit, labelling, silver nitrate handling if the process needs it, and silver-bearing waste. The clearing chemistry is the formulary’s iron-silver clearing sequence where the process is an iron-silver one.

Safety classification

Level B, set by the toning chemistry and the sensitiser salts rather than by the printing. Three criteria of the rubric apply: reagents classified for acute toxicity or sensitisation, a waste stream requiring collection rather than discharge, and an ultraviolet source where the alternative process needs one.

Nothing on this page requires a fume cupboard, and any route that turns out to require one is outside the capstone specification. That is the rule the permitted list below is built from, and it excludes work rather than being negotiated around.

What is not a hazard here, and why. The alternative-process printing itself — laying a negative on a coated sheet, exposing it, and washing it — is Level A work and would be so on its own. Coating a sheet with a made-up sensitiser is Level A. What raises the whole page is two things: the toner, which is a bath of a compound classified for acute toxicity whose waste may not go to a sewer; and the weighing of sensitiser salts as powders, if you make your own sensitiser rather than buying it made up. A reader who buys a pre-coated cyanotype sheet and tones with nothing has a Level A session, and the level is a property of the route rather than of the page.

⚠One raised step, and one route the capstone excludes outright

Weighing anhydrous sodium sulfide is a Level C operation and stays one. Part XX ruled on this on 5 September 2026: the solid is acutely toxic by ingestion and skin contact and deliquesces, the stock is made once, outside any toning session, under Level C controls, and a tray of dilute working toner is a Level B operation.

The capstone permits no Level C work at all. So the sepia route is available here in three forms and not in a fourth:

• Buy a packaged sepia toner and dilute it. The maker’s own current safety data sheet governs, and you read it before you buy rather than after.
• Use Kodak’s hypo-alum bath T-1a, which reaches a silver sulfide image without a sulfide reagent ever being handled, by acidifying hot hypo until it precipitates its own sulfur. Part XX calls it Level B outright — and says in the same breath what that trade actually is: a half-strength fixing bath deliberately acidified and held at 49 °C is exactly the condition under which thiosulfate releases sulfur dioxide, so Kodak’s own limit of 49 °C and twenty minutes is a control rather than a convenience. A Level C reagent traded for a gas with a workplace exposure limit is a reduction, not an elimination.
• Use a bought sodium sulfide stock solution, if you can obtain one, dosed in dilution.
• Making the sulfide stock yourself from the solid is outside this capstone. If your project needs it, the project changes.

And the substitution people reach for is not the escape it looks like. “Odourless” sepia toners are thiourea toners, Moersch state it flatly, and thiourea carries Warning with H302, H351 (suspected of causing cancer), H361d and H411. Princeton’s guidance advises avoiding it wherever possible. Trading a smell for a suspected carcinogen is a decision to make with the sheet in front of you, not a default.

Hazards

What	Classification and the control it sets
Selenium toner (packaged)	Harman’s sheet of 18 July 2024: Warning, GHS07, Acute Tox. 4, Skin Sens. 1, Aquatic Chronic 3, H302, H317, H412. The maker calls it a toxic chemical and strongly recommends working in a well-ventilated area, preferably with extraction, and rubber gloves in all use and disposal
Sulfide toners	Hydrogen sulfide is released, smells of rotten eggs, is a health hazard, and fogs unexposed photographic material. Moersch: not used in a darkroom with no ventilation and little fresh air; the risk is ruled out by toning outdoors and watering the print twice before returning indoors
Thiourea toners	Warning; H302, H351, H361d, H411. Highly alkaline, pH up to 13.4, and toning times not exceeding one minute because the gelatin softens
Potassium ferricyanide bleach	Never acidified — the incompatibility matrix gives hydrogen cyanide as the product of a cyanide or ferricyanide meeting an acid
Iron and silver sensitiser salts as powders	Handled with the fine-particulate precautions of Part II. Silver nitrate is Danger with H272, H290, H314, H318, H360D, H400, H410, and is weighed and dissolved with goggles on
Ultraviolet source	Enclosed or interlocked so that direct exposure of eyes and skin is impossible. The assessment is made on the source, not on your intentions
Gold and noble-metal solutions	Expensive rather than especially dangerous; their waste is still collected for recovery

Two absolute rules for the room. No acid comes near a sulfide bath — that means the stop bath and any acid fixer are out of the room or sealed before the toner is opened, and a print is rinsed thoroughly after an acid bleach before it enters a toner. And all photographic material leaves the room, because the gas that harms you also fogs the paper you have been printing the set on.

Required PPE

Sealed chemical splash goggles, nitrile gloves and an apron for every bath on this page, and for the selenium bath the maker’s own instruction of gloves in use and in disposal. Tongs rather than fingers, one pair per bath, never interchanged. Eyewash and a spill kit within reach before the first bottle is opened. For a UV exposure, the enclosure is the control and eyewear is the backup; if the answer to “what stops the light reaching my eyes” is a pair of glasses, the unit is not finished.

Ventilation

Local extraction, or a fan at an open window, and never an enclosed space. This is the one page in the capstone where ventilation is controlling a specific airborne hazard rather than diluting an odour: hydrogen sulfide from a sulfide bath and its first rinse, and the vapour above a selenium bath whose maker asks for extraction by name.

Where you have neither, the course’s own sourced route is outdoors: Moersch state that the risk from a sulfide bath can be ruled out by toning outdoors and watering the print twice before returning indoors. That is a manufacturer’s instruction rather than a workaround, and it is the honest recommendation for a reader without extraction — with the obvious conditions attached, that the containers travel with you, that nothing is poured on the ground, and that the waste comes back in its labelled bottle.

Materials

Material	Quantity	Note
Prints for treatment, from Stage 4	2 or 3	Fully fixed and fully washed. Toning reveals every processing shortcut
The matched untoned control	1 per toned print	Printed from the same map in the same session. This is the instrument, not a spare
Paper or plates for the alternative process	4 to 6 sheets	Pre-coated, or your own coating stock
The negative for the alternative-process print	1	By the declared route — see below
Unexposed control sheet	1 per batch	Carried through for Stage 6’s residual tests
Labelled waste containers	2 or 3	Toner and first rinse; clearing bath and first wash; and the ordinary streams

Chemicals

Chemical	Quantity per session	Form
The chosen toner	500 mL to 1 L of working solution	At the maker’s or the formula’s stated dilution — Harman give 1+3 for tone change and 1+20 where the primary reason is protection, at 20 °C ± 1
Potassium ferricyanide and potassium bromide bleach, for an indirect sepia route	500 mL of working solution	The rehalogenating bleach; never acidified
The alternative-process sensitiser	per the process	Bought made up, or coated onto a bought pre-coated sheet, unless you are formulating it under Stage 2’s controls
Clearing bath for the chosen process	per the process	The iron-silver clearing sequence or the process’s own
Ammonium thiosulfate fixer	as the process requires	Non-hardening, and out of the room before a sulfide bath is opened

Equipment

Unchipped enamel, hard rubber or plastic trays — never metal, which Kodak state explicitly for toning solutions. Dedicated tongs per bath. A thermometer. A UV unit or a reliable sunny site with a way of timing a dose. A coating rod or brush and a level surface if you coat. A drying arrangement that is not the one your silver prints use. The densitometer in reflection mode, if you have the attachment, for the matched-patch measurement. None is consumed and none appears in the table below.

Estimated cost

£££ on the planner’s bands, and it is the dearest stage in the capstone for one reason: the alternative-process consumables. Cyanotype is at the bottom of that range and platinum-palladium at the top, by more than an order of magnitude per sheet. Toner is a smaller cost but a real one, and it is bought as a bottle rather than by the millilitre.

Estimated consumables cost

Every figure with a source is the planner’s own dated UK price and every quantity comes from the Materials and Chemicals sections. The run costed is one treated-print session: one silver print toned with its matched control, plus one cyanotype from a pre-coated sheet, with spares.

Consumed	This session	Sourced price	Cost this session
Variable-contrast RC paper, 8 × 10 in	4 sheets — the toned print, its control and two spares	£33.50 for 25 to £96.18 for 100	£3.84 to £5.36
Paper developer concentrate	50 mL	£10.52 per 500 mL to £20.03 per 1 L	£1.00 to £1.05
Stop bath concentrate	15 mL	£10.66 to £12.18 per 500 mL	£0.32 to £0.37
Rapid fixer concentrate	60 mL, as two baths	£21.05 to £25.98 per 1 L	£1.26 to £1.56
Pre-coated cyanotype paper, 8 × 10 in	4 sheets	£18.95 for 20 to £36.95 for 50, that is £0.74 to £0.95 a sheet	£2.96 to £3.79
Toner concentrate, any kind	100 mL of concentrate	£11.87 for 150 mL of sepia, £21.95 for 946 mL of selenium, £32.99 for 250 mL of gold, checked 7 September 2026	£2.32 to £13.20, according to which chemistry
Washing aid	200 mL of working solution	£12.83 for a powder making 3.8 L of working bath	£0.68
Iron and noble-metal sensitiser salts	per sheet, if you coat your own	The cyanotype pair is priced, at £17.99 per 230 g each; ferric oxalate and the noble-metal salts are gaps the file names and cannot price	—
Clearing-bath chemicals	500 mL of working solution	The price file could not price them	—

The priced rows come to about £12.38 to £26.01 for one session, and that is a floor and a wide one: the toner line alone runs £2.32 to £13.20 according to which chemistry you tone in, and two of the nine consumables — the hand-coating sensitisers and the clearing baths — still have no sourced price. The sensitiser is the row that decides whether this stage costs a few pounds or a hundred. Cyanotype remains the only alternative process the price file can price through, and it is the cheap one. Treat the table as evidence about the silver half of the session and the planner’s bands as the only honest guide to the other half.

Waste streams

This is the stage where waste separation is a working practice rather than a paragraph, and it is planned as a room layout before anything is diluted.

• Toner and its first rinse, every drop, in a labelled container of its own for licensed disposal. Kodak’s guidance for an amateur as a domestic user lists what may go to a sewer — developers, stop baths, fixers after silver recovery, wash waters — and then lists what must not, naming selenium toners first. Harman say the same in their own words: do not empty into drains, dispose of the material and its container at a hazardous or special waste collection point.
• Sulfide toner waste in its own container, which has never held a stop bath or a fixing bath, and never will.
• Bleach and its rinse, ferricyanide-bearing, collected and never acidified.
• Clearing baths and first washes from the alternative process, collected rather than drained, because they carry both metal and sensitiser.
• Spent fixer, silver-bearing, to recovery as usual.
• Gold and noble-metal solutions, collected for recovery — expensive rather than especially dangerous, but the recovery is worth doing.

Local regulation governs disposal and this page gives no jurisdiction-specific instruction. For this stage more than any other, find out what your local hazardous-waste route actually is before you mix the toner, because the answer may change which toner you choose. Read the disposal caveat.

Alternative route

No extraction. The sourced route is outdoors, and it is a manufacturer’s instruction rather than a compromise: Moersch state that the risk from a sulfide bath is ruled out by toning outdoors and watering the print twice before returning indoors. The same arrangement — a table outside, containers carried out and back, nothing poured away — serves a selenium bath, whose maker asks for a well-ventilated area preferably with extraction. What this route cannot do is give you a temperature-controlled bath in cold weather, and toner activity is temperature-dependent, so the session record has to carry the actual temperature rather than the intended one.

If working outdoors is not available either, the honest permitted list narrows to routes whose reagents do not evolve a gas and do not ask for extraction: iron-blue (Prussian blue) toning and gold toning by GP-1, both of which are metal-replacement baths worked at room temperature. Their cost is stated rather than hidden — ILFORD note that blue (iron) and red (copper) toners may not give extra protection and the image might fade, so a portfolio toned that way makes an aesthetic claim rather than a permanence one, and the permanence statement must say so.

No UV unit. Daylight prints every process in this cluster, and it is what all of them were invented under. The cost is a dose you cannot set: an exposure becomes a judgement against a test strip on the day, and a cloudy afternoon and a clear one are different light sources. Print a step wedge alongside every sheet and read the dose off it rather than off a clock. What you lose is repeatability between sheets made on different days, which matters for a set — so make the alternative-process prints for the portfolio in one session if you are printing by daylight.

Unable to handle a class of chemical. The substitution table in the specification governs. Two cases recur here. A reader who cannot handle selenium has sulfide, gold and iron-blue routes and loses nothing structural, though the protective-toning discussion in the chemistry report changes because the makers’ claims differ by toner. A reader who cannot handle any toner at all cannot satisfy requirement 9, and the honest response is to record it as not attempted with the reason, complete requirement 10, and declare the substitution — the specification’s rubric penalises the silence rather than the circumstance.

No pre-coated paper and no coating facility. Cyanotype pre-coated sheets are the cheapest complete route through requirement 10 that the price file can price, and they need no weighing at all.

Preparation

Choosing which image to tone

It is a decision about the picture, and it is made in three clauses written down before anything is diluted:

1. What you want the image colour to do, in words that could be wrong. “Warmer, so the figures read as remembered rather than observed” is a claim; “nicer” is not.
2. What you want the deep tones and the upper scale to do. These move in different directions with different toners, which is the whole reason there is more than one.
3. Which mechanism can deliver it, named: sulfide conversion, selenium conversion, or a metal deposition or replacement.

And then the cost of that mechanism, in three currencies. Density: Kodak state that Sepia, Sepia II Warm and Brown toners reduce print densities, so prints for them are developed fully and made slightly darker than normal, while Rapid Selenium Toner tends to intensify the image, so development may be shortened slightly — and both effects depend on the paper emulsion and grade. Hazard: the table above. Waste: whether the bath can go to a sewer after recovery or must be collected for licensed disposal, which for selenium is settled and named.

📷Toning cannot rescue a print, and Kodak say so

Kodak’s own guideline is that toning cannot disguise poor print quality, and that a good candidate has a full tonal scale with good detail in the highlights and shadows. A print you are half-satisfied with does not become satisfying in a toner; it becomes a half-satisfying print of a different colour, and you will have spent the toner and the control sheet finding that out.

Choose from the strongest prints in the set, not from the ones you have spare.

Printing for the toner rather than toning a print

Apply the compensation you measured in Part XX, so that the toned print arrives at the intended density and contrast after treatment. The arithmetic is your own: the density change you measured at a mid-tone patch, divided by your paper’s measured density per stop, gives the exposure correction in stops. The course publishes no general figure for this and will not, because the change depends on the paper, the toner, the dilution and the time.

Print a matched untoned control from the same map in the same session. This is the instrument. The eye cannot say in the absolute whether a print is a third of a stop light or whether a brown is warm, and it is very good at saying which of two adjacent sheets is darker. A toning session run without a control produces a toned print and no knowledge.

Choosing the process and declaring the negative route

The negative problem is the one that catches people, and it is arithmetic rather than taste. There is no Callier effect in contact printing, so the UVA density range the negative needs equals the logarithmic exposure scale of the sensitiser. Put a negative made for grade 2 silver paper — about 0.90 — in front of a New Cyanotype whose scale is about 2.2 and the negative controls less than half the range the process can span: the print comes out flat and dark at once, a small tonal excursion sitting low, nothing near paper white and nothing separating the deep tones.

Process	Published exposure scale or required negative range	Where it comes from
Classic cyanotype	scale about 0.9; UVA negative range 0.9 to 1.2	Ware, Cyanomicon
New Cyanotype	1.6 to 2.4	Ware, Cyanomicon
Kallitype	about 1.8	Sandy King; measurement condition not stated
Van Dyke Brown	up to 1.85	Kit instructions; measurement condition not stated
Platinum, print-out	1.5 to 1.8, depending on humidity	Ware, Platinomicon Table 7.1
Palladium, print-out	2.0 to 2.4, depending on humidity	Ware, Platinomicon Table 7.1
Salted paper and albumen	no figure published	Reilly, who gives a measurement instead: print a 21-step wedge to full maximum density, count the steps still separable, and the density difference across them is your target
MULTIGRADE RC at filter 2, for comparison	0.90	ILFORD, under ISO 6846:1992 in visible light

Three negative routes, and you declare which you used and what it cost the picture.

• Develop the film further. Ware’s instruction is normal exposure and development 75 to 100 per cent longer than the silver-printing time, aiming at a contrast index of 0.7 to 1.3. What it costs is grain, highlight separation, and — the important one for a capstone — the negative itself, because Ware is explicit that those contrast indices are more or less incompatible with normal silver printing. One negative cannot serve both, so this route means the alternative-process picture is shot and developed for that purpose.
• Use a staining developer. A pyro stain is opaque in the near ultraviolet and nearly invisible in green, so the negative has a modest visual range and a long printing range at 365 nm. What it costs is your ability to measure what you have made, because a visual densitometer reading no longer describes the printing range.
• Print a digital negative. Legitimate in this course and published in Part XXI as Ware’s printer-agnostic calibration — a 100-step tablet, a deliberate overexposure to find the blocking point, and a Standard Printing Exposure computed from it. Its advantage for a portfolio is real: every negative comes out at close to the same density and contrast, so a body of work is consistent in a way camera negatives are not. Its cost is a calibration redone whenever the printer, ink, driver setting or film changes. Declare it. A capstone about traditional process that used a digital negative and did not say so has a hole in its record exactly where a reader would look.

Then choose the process from the measured fields of your Part XXV atlas rows rather than from reputation, with cost per sheet and hazard as explicit criteria alongside image colour and tonal scale. The honest ordering for a capstone: cyanotype is cheapest, needs no silver and no clearing chemistry beyond water, and is fully priced in the course’s shopping data; platinum-palladium sets the top cost band and is the only route that will make a reader think about whether a sheet is worth exposing.

Procedure

The toning session

1. Prepare the room as a layout, before anything is diluted. All photographic material out. Stop bath and any acid fixer out of the room or sealed. Trays laid out with their own tongs, in the order they will be used, with a labelled waste container beside each. Eyewash and spill kit within reach.
2. Confirm the prints are fully fixed and fully washed. Toning reveals every processing shortcut, and a print carrying residual fixer into a bleach makes the bleach act as a reducer — Moersch’s own warning — after which redevelopment is impossible and at least the highlights are gone irretrievably.
3. Mix the toner to the stated dilution and bring it to temperature. Harman’s figures for their selenium toner: 1+3 for normal toning, 1+20 where the primary reason is protection with minimal tone change, at 20 °C ± 1, with protection at 1+20 complete in 2 to 4 minutes.
4. Set up the three-dish arrangement the maker describes: plain water either side of the toner, the holding dish about 4 °C warmer, and the untoned control kept in it to refer to. Do not watch the print continuously in the toner; the maker’s own note is that continuous observation makes subtle changes harder to see.
5. Tone to the time and temperature in the plan, and record what actually happened rather than what was intended.
6. Stop and wash. Harman: 30 to 40 seconds in the second holding dish, then two minutes for RC prints and at least thirty minutes for fibre — or the optimum permanence sequence, in which the washing aid replaces the water after toning and the final wash is thirty minutes.
7. Record the hue against the control, and the matched-patch densities before and after, under the recorded judging station. If you have the reflection attachment, this is a measurement; if not, it is the visual comparison method of Stage 4, recorded in stops against the control with its limits stated.
8. Route every drop of toner and first rinse into its labelled container.

The alternative-process print

9. Coat, or take a pre-coated sheet, and open the coating record: the sensitiser and its batch, the coating method, the volume per sheet, the humidity, and the drying conditions and time.
10. Expose by dose rather than by time. A step wedge alongside every sheet, so that the exposure is read off the print rather than off a clock — which is the only way daylight and a UV unit produce comparable records.
11. Develop or wash-develop, then clear, by the process’s own sequence. The clearing step is not optional and it is not a rinse: it removes the residual iron or the unreduced salts that would otherwise stain and shorten the print’s life.
12. Give the process whatever after-treatment its permanence depends on — the toning step of an iron-silver print, the clearing sequence of a platinum print — and record it as part of the object rather than as a finish.
13. Finish to the same standard as the silver prints: dry, flat, spotted, trimmed, and made for the presentation format decided in Stage 4.

Expected observations

The toned print will not look like the control in more ways than one. Expect image colour, and expect a density change in the direction the maker states — sepia and brown toners reduce densities, selenium tends to intensify. Expect the deep tones to change first and most: a partial conversion is the usual result rather than the exception.

The first rinse after a sulfide bath smells worse than the bath. Moersch say so, and it is the practical reason the outdoor route waters the print twice before it comes back indoors.

A cyanotype looks wrong when wet and right when dry, and it goes on darkening for a day. Judge nothing about an iron-blue print on the day it was made.

A negative made for silver will disappoint on any of these processes, and the disappointment has a specific shape: flat and dark together rather than merely contrasty. If that is what you see, the negative route is the diagnosis and not the exposure.

What is happening chemically

Three conversions, named for the chemistry statements requirement 9 and requirement 10 ask for.

Sulfide toning replaces the image silver with silver sulfide, one of the least soluble silver compounds there is, which is why the 1928 primer records that where great permanency is required prints should preferably be toned to a silver sulfide image. By the indirect route the image is first rehalogenated by a ferricyanide-bromide bleach and then redeveloped in sulfide:

Ag + [Fe(CN)₆]³⁻ + Br⁻ → AgBr + [Fe(CN)₆]⁴⁻

Bleaching: the image becomes a halide again, in place

2 AgBr + S²⁻ → Ag₂S + 2 Br⁻

Redevelopment: the halide becomes the toned image

Both are Part XX’s own equations, reproduced here because they are what the chemistry statement has to name, and the direct route reaches the same compound without the halide step at all.

Selenium toning converts image silver to silver selenide, and Kodak state the conversion in those terms for their own toner. Two cautions, and the second is why no equation is written here. The conversion is partial in practice and time-dependent, which the report must state rather than avoid. And the active selenium species differs between products: modern safety data sheets disclose a selenite or a selenate, while the selenosulfate of the historical route is named by no modern sheet the course has read. Part XX is explicit that neither sheet licenses a claim about the other, so the honest statement names the compound formed — silver selenide — and the product’s own disclosed component, and stops short of a balanced equation this course cannot source for the bath in your tray.

An iron-blue image is not silver at all. A cyanotype’s image-forming species is Prussian blue, an iron(III) hexacyanoferrate(II) held in the paper’s own fibres with no binder and no silver anywhere. That is why the conservation atlases identify it by a completely different signature from a silver-gelatin print, and it is why its storage requirements in Stage 6 will contradict those of every other print in the portfolio.

Data to record

The toning session record: the three-clause intention as written before the session; the toner, its document and its date, its dilution and its temperature; immersion and lift times; the stop and wash times and route; the ventilation arrangement; which waste went into which container; the hue described against the control; and the matched-patch figures before and after with signs.

The compensation record: the measured density change, the paper’s measured density per stop, the correction in stops, the map version it was applied to, and the anchor test strip.

The coating and exposure record: sensitiser and batch, coating method and volume, humidity, drying time; the negative and its declared route; the light source, the dose and how it was measured; the development, clearing and after-treatment as performed.

The atlas row, if you are contributing one: the fields Part XXV’s comparison atlas already defines, filled from this print rather than from a reference.

Analysis

The chemistry statement for each treated print

Three sentences, in your own words, for each:

1. What the image is made of now. Silver sulfide; silver selenide, partially converted; Prussian blue in the paper fibres; reduced silver on an iron-silver print. Name the compound.
2. By what reaction. The equation, checked, with the bath that ran it.
3. What remains in the paper that should not. Unconverted halide from a partial bleach; residual iron from an incompletely cleared iron print; residual thiosulfate from the fixing that preceded the toner. This is the sentence that connects to Stage 6, and it is the one people leave out.

✕The claim to be careful with, and the standard that declines to help

Toning is recommended by manufacturers as protection against oxidising gases, and Kodak state that toning converts the silver image to an inert compound and that all their toners protect it. ILFORD are more discriminating: sulphide, polysulphide and some metal replacement toners give a protective effect, while blue (iron) and red (copper) toners may not and the image might fade, and dye toners do not.

What none of them gives you is a measurement of your print. ISO 18915 is the standard written for exactly that question and its published scope says it describes methods for evaluating the effectiveness of chemical conversion treatments, does not recommend general or specific treatments, and puts treatment times and temperatures outside its scope. It is a measuring instrument, not a specification a print can be certified against.

So the honest sentence names the manufacturer’s claim as the manufacturer’s, states that the degree of conversion in your print was not measured, and stops there. Stage 6 will ask for it in that form.

The judgement the stage exists to force

Lay the treated prints beside the silver set, under the recorded judging station, at the recorded distance. Then answer one question in writing:

Does this print belong to the same body of work, or is it a different statement about the same subject?

Both answers are acceptable if they are argued. A toned print that shifts the whole set warmer may be exactly what the sequence needed, or it may be the one object that makes the other seven look like a different project. A cyanotype of a subject the silver prints also treat may extend the argument or may simply be the same picture in blue.

What is not acceptable is an unexamined inclusion — a treated print in the portfolio because the specification asked for one. That is the state the requirement is designed to expose, and the rubric’s coherence criterion is where it shows up.

If the answer is that it does not belong, you have two moves: reprint it so that it does, or include it as a deliberate counterpoint and say in the portfolio statement that that is what it is. Both are better than pretending.

Troubleshooting

What you see	Likely cause	What to do
Highlights vanish during bleaching	Residual fixer in the print: thiosulfate makes the bleach act as a reducer	Unrecoverable for that print. Rewash the remaining prints thoroughly before bleaching, and check the fixing sequence
Blue spots in a bleached print	A trace of iron in the ferricyanide bleach, classically from a defective enamelled tray	Use unchipped enamel, hard rubber or plastic; the 1928 primer’s remedy is potassium oxalate in the bleach, which dissolves the blue salt
Yellow stain over the whole toned print	Improper fixing before toning — Kodak name it as probably the major cause of stains in toned prints	Nothing recovers it. Two-bath fix the remaining prints and log the capacity
The toner works more slowly than last time	Capacity: Harman note that as the solution is used and ages the rate of tonal change becomes slower	Time by the result against the control, not by the clock, and record the bottle’s history
A print blisters or bleaches in a hypo-alum bath	Above 49 °C, or beyond twenty minutes	Kodak’s own limits. Hold the temperature and time; this is a control rather than a guideline
A cyanotype is flat and dark together	The negative’s range is far shorter than the process’s exposure scale	The negative route, not the exposure. Re-read the density-range table and choose a route
An iron-silver print will not clear	See Part XXIV	The clearing sequence and its freshness
The whole box of paper starts printing grey	Sulfide fog: a very small quantity of hydrogen sulfide converts enough silver halide to produce severe fog	Photographic material never shares a room with sulfide toning. Discard the affected box; the paper cannot be recovered

Clean-up

Return the room to a state in which ordinary printing can resume, and that is a real task rather than tidying. Every toner tray and its tongs are washed separately and stored separately, and they do not return to the ordinary tray stack. Every waste container is capped and labelled with what is in it and the date. The bench is washed down. The room is ventilated for as long as it takes for the smell to go, and the paper stock comes back in only after that.

Then, before the next silver session, make one test print on a sheet from the box that was out of the room, and look at its base white. That is a five-minute check that tells you whether the separation worked.

Storage

Treated prints are stored apart from the untreated ones until Stage 6 decides their enclosures, because one of them will need a different board from the others. Interleave flat, in the dark, cool and dry.

Toner concentrates in their own containers, tightly closed, labelled and dated, in a place where nothing acidic is stored. A part-used toner is dated on the label as opened, because activity falls with age as well as with use.

Sensitiser solutions by their own process’s rules — most are light-sensitive and some are short-lived — and any silver nitrate solution in a brown bottle away from the working surfaces.

Disposal considerations

The chemistry of the decisions above: selenium compounds are named first on the list of what an amateur must not send to a sewer, and the maker’s own instruction is a hazardous or special waste collection point for the material and its container. Sulfide waste meets no acid, ever, because acid and sulfide give hydrogen sulfide. Ferricyanide waste is never acidified, because acid and a ferricyanide give hydrogen cyanide. Clearing baths and first washes carry both metal and sensitiser and are collected rather than drained. Gold and noble metals are collected for recovery, which is economic as much as environmental.

Local regulation governs disposal and this page gives no jurisdiction-specific instruction. For this stage the practical consequence is worth stating plainly: find out what your hazardous-waste route is before you choose a toner, because a route you cannot use is a toner you cannot run. Check your local regulations; the disposal page explains why the answer is jurisdictional.

Questions

1. Write the three-clause toning intention for one of your prints, in the form that could be wrong.
2. Your paper loses 0.10 in density at a mid-tone patch on toning, and measures 0.50 density per stop. What exposure correction do you apply, and to which version of the map?
3. Your negative has a density range of 0.95 and you want a New Cyanotype. State the problem in terms of exposure scale, and give two routes out of it with what each costs.
4. Why is a stop bath’s presence in the room a hazard control question rather than a housekeeping one on a sulfide toning night?
5. Write the three-sentence chemistry statement for a selenium-toned print, including the sentence about what remains in the paper that should not.
6. Your toned print is the strongest object in the portfolio and it makes the other seven look like a different project. Argue for including it, then argue for dropping it, in two sentences each.

Further experiments

Bleach a test strip from the toned sheet. It is the only way to find out how much of the image actually converted, and Part XX’s assignment provides for it. If you do it, say so — it is the most informative sentence available for a permanence statement, because it turns “toned” into a measured degree.

Tone the same picture at two dilutions and compare. Harman publish 1+3 for tone change and 1+20 for protection with minimal tone change; making both, from one map in one session, shows you what the two dilutions actually do on your paper, and gives you a matched pair for the portfolio decision.

Print one negative in two alternative processes. The atlas row asks for measured fields; two rows from one negative, exposed and cleared on the same day, is the cleanest comparison you can make and it contributes directly to Part XXV’s atlas.

Calibrate a digital negative properly, once. Ware’s 100-step tablet, the deliberate overexposure, the blocking point and the Standard Printing Exposure. It is an afternoon, it is the only route that lets you set a density range to a number you chose, and once done it makes every subsequent alternative-process print in the portfolio consistent with the others.

Check your understanding

Question 1. Your capstone plan calls for a sepia print by bleach and redevelopment, using a sodium sulfide stock you would weigh and make yourself. Is that permitted?

• Yes, provided the weighing is done with a particulate mask and goggles
• Yes, since Part XX runs a sepia lab at Level B
• No: weighing anhydrous sodium sulfide is a Level C operation under Part XX's ruling, and the capstone permits no Level C work — so the route is available only from a bought toner, a bought stock solution, or the hypo-alum bath, which reaches silver sulfide without a sulfide reagent being handled
• No: sulfide toning is excluded from the capstone entirely

Show the answer and why

Answer: No: weighing anhydrous sodium sulfide is a Level C operation under Part XX's ruling, and the capstone permits no Level C work — so the route is available only from a bought toner, a bought stock solution, or the hypo-alum bath, which reaches silver sulfide without a sulfide reagent being handled

Part XX's sepia lab is Level B precisely because the stock-making is not part of it — the ruling separates the operation from the substance, and the Level C weighing happens once, on a different day, under different controls. The capstone's own boundary rule forbids Level C work of any kind, so what it forbids is that one operation rather than the process. Three routes to a silver sulfide image remain, and the hypo-alum bath is the interesting one because it trades a Level C reagent for a sulfur-dioxide risk that Kodak control with a temperature and a time limit — a reduction rather than an elimination, and the page says so in those terms.

Question 2. A negative with a density range of 0.90 is contact-printed on a New Cyanotype whose exposure scale is about 2.2. What does the print look like, and why?

• Contrasty, because the process is more contrasty than silver paper
• Flat and dark at once — a small tonal excursion sitting low, with nothing near paper white and nothing separating the deep tones — because the negative controls only 0.90 of the 2.2 log units the process spans
• Normal, since contact printing has no Callier effect to worry about
• Blank, since the sensitiser needs at least 1.6 to record anything

Show the answer and why

Answer: Flat and dark at once — a small tonal excursion sitting low, with nothing near paper white and nothing separating the deep tones — because the negative controls only 0.90 of the 2.2 log units the process spans

The absence of a Callier effect is exactly why the arithmetic is so direct: in contact printing the negative's UVA density range should equal the sensitiser's logarithmic exposure scale, so a shortfall is a shortfall with nothing to disguise it. The clear film base passes enough light to drive the shadows to maximum blue, while the densest highlight is nowhere near enough to hold back the paper white — so the picture is built from the bottom third of the process's range. The diagnosis is the negative route rather than the exposure, and the three routes out of it each buy the range with something different.

Question 3. You have no extraction. Which toning route does this page recommend, and on what authority?

• A thiourea toner, because it is odourless
• Toning outdoors, watering the print twice before returning indoors — which is Moersch's own published instruction for a sulfide bath and serves a selenium bath too, with the containers carried out and back and nothing poured away
• Selenium at 1+20, because the short time limits the exposure
• None: without extraction, requirement 9 cannot be attempted

Show the answer and why

Answer: Toning outdoors, watering the print twice before returning indoors — which is Moersch's own published instruction for a sulfide bath and serves a selenium bath too, with the containers carried out and back and nothing poured away

The recommendation is a manufacturer's instruction rather than an improvisation, which is what makes it citable — and it comes with its own conditions, including bringing the waste back in a labelled container. "Odourless" is the trap: Moersch state flatly that odourless sepia toners are thiourea toners, and thiourea carries suspected carcinogenicity and reproductive toxicity, so the smell has been traded rather than the hazard removed. Shortening the immersion does nothing about a bath standing open in an unventilated room. And the requirement is attemptable by two further routes that ask for no extraction at all, iron-blue and gold, at the stated cost that the makers do not claim protection for them.

Question 4. What does the specification require you to say about a treated print that, laid beside the silver set, clearly does not belong to it?

• Nothing: the requirement asks for a toned print, and you have one
• That it should be reprinted until it matches the set
• Either that you reprinted it so that it belongs, or that you included it as a deliberate counterpoint and the portfolio statement says so — the judgement being the deliverable, and an unexamined inclusion being what the requirement is designed to expose
• That the alternative process was the wrong choice

Show the answer and why

Answer: Either that you reprinted it so that it belongs, or that you included it as a deliberate counterpoint and the portfolio statement says so — the judgement being the deliverable, and an unexamined inclusion being what the requirement is designed to expose

Requirements 9 and 10 are not satisfied by the existence of a treated object; the stage exists to force a decision about the body of work, and the rubric's coherence criterion is where an unmade decision becomes visible. Both real answers are legitimate — a counterpoint that is argued is a coherent choice, and so is a reprint. What is refused is a print in the portfolio because the specification asked for one, with nothing written about how it sits with the rest. Reprinting until everything matches is one option among two rather than the requirement, and blaming the process is a way of not making the judgement.

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