The printed-out image that bleached away in the fixer

Owned by Break/Fix — the printed-out image that faded, whose first case names this entry and adds a visible discriminator it did not carry: black stains, which Reilly attributes to unremoved silver nitrate meeting the fixer and which none of the other causes produces, so their presence settles the diagnosis without reading the record at all. That page also supplies the second discriminator, which is whether the fully exposed margin is weak as well as the picture. Part XXIV’s break/fix page carries the same fault for the iron-silver processes. This entry was written earlier from how fixer works and the encyclopaedia.

What you see

A print that was rich and is thin. A printing-out image comes out of the frame a deep purple or red-brown; in the fixing bath it lightens, shifts colour, and — when this fault occurs — keeps going, until the shadows are a weak brown and the highlight detail is gone.

Some of that is normal and some of it is not, and separating the two is the whole difficulty.

Likely causes

1. The wrong kind of fixer. Photographers’ Formulary are explicit for the kallitype: do not use a standard photographic fixing bath, because the finely divided, unprotected silver metal will be etched from the print.
2. Too long in it. Their limit is not more than five minutes, because “a longer soak will cause the print to fade.” Bostick & Sullivan’s salted-paper sheet says the same thing in one line: over-fixing can lead to bleaching of the image, while under-fixing will cause archival permanence issues.
3. Toning in the wrong order. These processes are toned before fixing precisely so that the image is converted into something the hypo will not attack.
4. Under-exposure. These are print-out processes and they lose density in processing by design, so the correct exposure is an over-print.

What is happening: the chemistry and physics

Part of the change in the fixer is optical, not chemical, and it is supposed to happen. Reilly’s account is the clearest in the corpus: dissolving the unreduced silver chloride changes the refractive index of the whole system and packs the silver particles more closely together, and that is why prints with a rich purple or brown colour after exposure change to a reddish or yellowish brown in the fixing bath. Nothing has been lost; the same silver is scattering light differently. On drying it changes again, becoming darker and colder as the distances between particles change once more.

The rest is the fixer doing to the image what it does to the unexposed salt. A thiosulfate bath is a silver solvent — Part XI owns the complex chemistry — and a printing-out image is colloidal silver with an enormous surface area and, on a salted or Van Dyke paper, no binder over it at all. A gelatin emulsion protects its silver by burying it. These processes do not.

So there is a window: long enough to remove the unexposed silver salt, short enough not to dissolve the image. Photographers’ Formulary put both edges of it in two sentences — everything must come out for stability, and more than five minutes fades the print.

!The confirming test: half a print, two fixing times

Cut an exposed, toned print in two. Fix one half for the recommended time and the other for twice it, then wash, dry and compare.

• The longer half is markedly thinner: the bath is etching the image, and the fix is a shorter time, a weaker bath, or a different bath.
• They match: the loss you saw was the optical change Reilly describes plus dry-down, and the exposure — not the fixer — is what needs to move.

Then check the order of operations. Bostick & Sullivan’s own instruction for kallitype, Van Dyke, salt and albumen prints is to follow the standard rinsing and clearing for the process but not to fix before toning; and their POP instruction is to tone, then fix, noting in the same breath that the fix might bleach out some of the remaining silver. A print fixed before toning has met the hypo at its most vulnerable.

Diagnostic questions

• What was in the fixing bath? A plain thiosulfate solution at about 50 g/litre is what these sheets specify; a rapid or hardening photographic fixer is a different and much more aggressive reagent.
• How long, and at what temperature? Five minutes is the Formulary’s ceiling for kallitype; four to five the salted-paper figure.
• Was the print toned first? Order matters more here than almost anywhere else in the course.
• How dark was it out of the frame? Bostick & Sullivan’s targets are explicit: over-print by one or two shades for POP, and stop a salted paper at about half to two-thirds the desired final darkness because it darkens later.
• Was the pre-rinse done? The POP sheet’s two-to-three-minute rinse removes excess silver before the toner and the fixer see it, and skipping it changes what both baths have to work on.
• Are there black stains? This is the one cause on the list that announces itself, and the owning page puts it first for that reason: Reilly attributes black staining specifically to free silver nitrate carried unrinsed into the fixer, and none of the other causes produces it. If the stains are there you have the answer without reading the record at all.
• Is the margin weak too? The margin was exposed through nothing, so it shows the strongest tone this sheet and this processing could reach. A weak margin convicts the sheet or the bath; a strong margin beside a weak picture convicts the exposure or the negative.

Corrective action

A bleached print cannot be brought back, and the density that went into the bath is in the bath.

Re-print with the exposure the process asks for, which is more than looks right in the frame.

Fix in a plain, dilute thiosulfate bath for the stated time and no longer, and time it rather than watching it.

Tone before fixing where the process says so.

And do not solve it by under-fixing. Both sheets say the same thing from opposite directions: the excess silver salt and all the thiosulfate must come out for the print to be stable, and a print rescued from bleaching by a short fix is a print that will fade later.

Prevention

Use the process’s own fixer, not the one on the shelf from film work.

Time every bath, because the window between under- and over-fixing on these materials is measured in minutes rather than in tens of minutes.

Wash properly afterwards. The Formulary’s kallitype figure is 40 minutes in running water, or two to four minutes followed by a hypo-clearing agent and a 15 to 20 minute wash.

Judge exposure on the dried, finished print, and write down the over-print factor that gets you there.