Handling a sulphide toner and its waste

Purpose

To have a dilute sulphide bath on a bench for under an hour without an acid, a metal tray or a box of paper anywhere near it, and to get three waste streams into three containers afterwards.

When to use it

Any session in which a sulphide toner bath exists in the room — a bleach-and-redevelop sepia, a polysulphide bath, or a bought sepia kit’s part B. It governs the substance; the print’s route through the trays belongs to the toning session and to the sepia lab.

It does not cover weighing the solid. Weighing anhydrous sodium sulphide is a Level C operation in this course and stays one: it happens once, on a different day, under the controls its encyclopaedia page states, or the stock is bought ready made.

Before you start

You should already have read the sulphide lesson and the incompatibility matrix, and have a stock made or bought, labelled, capped and stored away from anything acid.

Level B. Chemical splash goggles rather than spectacles whenever the stock bottle is open or being poured; single-use nitrile gloves changed the moment one is contaminated inside; an apron. Run the ventilation check before the session: a through draught, running throughout. You cannot smell your way to safety here — the sense fatigues rapidly and cannot be relied on to warn of the gas — so the controls are dilution, a short bath life and the absence of acid.

On the bench: non-metal, dedicated trays, never sheet iron and never a chipped enamel one; dedicated tongs; three labelled waste containers standing apart from one another, each with its own funnel.

And the room is cleared first. Paper boxes, film and negatives are sealed and carried out before the sulphide stock is opened, because a very small quantity of the gas converts enough silver halide to fog a box you have been drawing on all season. The acid stop bath leaves with them.

Procedure

1. Carry the paper, the negatives and every acid — stop bath, acid or rapid fixer, clearing bath, vinegar, descaler — out of the room. Check the waste corner as well as the bench.
2. Open a window and run the fan, and leave both running until after the last container is capped.
3. Set the three waste containers out apart from each other, labelled and open: ferricyanide, sulphide, silver-bearing.
4. Fill the water trays first — soak, rinse, wash — and bring them into the band.
5. Mix the working bleach, if the route uses one, and cap its stock.
6. Mix the working sulphide bath last, with goggles on, and cap the stock and take it off the bench at once. The bath now exists and so does the smell, so the session is on a clock from here.
7. Give the print at least two minutes in cold running water between the bleach and the toner. That rinse is what keeps the acid of the bleach out of an alkaline sulphide bath.
8. Rinse for two minutes again after the toner, and route that first rinse to the sulphide container. The rule runs in this direction too: a print carrying sulphide into an acid is the carrier.
9. Wash for the maker’s published time and do not shorten it. A toned print holds residual sulphide, which goes on converting the image and is a source of the gas that fogs paper near the drying rack.
10. Discard the working toner at the end of the session rather than keeping it, and pour it through the sulphide funnel into the sulphide container.
11. Pour the spent bleach through its own funnel into the ferricyanide container. A funnel that has carried the bleach has carried acid, and it does not then go over a sulphide bottle.
12. Put the spent second fixing bath into silver-bearing waste.
13. Collect the remaining rinses and wash water rather than draining them, and say on each label what is in it.
14. Cap every container, wipe its outside, top up its running-volume line and add the date.
15. Wash the trays and tongs into the container their bath went to, and leave them to dry apart from the silver bench’s tongs.
16. Air the room before the paper comes back into it.

How you know it worked

• No acid was in the room from before the stock was opened until after the last cap.
• No photographic material was in the room at any point, and the room was aired before it returned.
• Every tray and every pair of tongs was non-metal and belonged to this bench.
• Three containers, three funnels, and no funnel crossed between them.
• The first rinse after the toner went to the sulphide container rather than to the sink.
• The working bath was discarded at the end rather than kept.

If a step fails

Step 1, an acid is found in the room after the stock is open. Cap the stock, leave the room, and take the acid out from outside if you can. This is the hydrogen sulphide case, and its short-term exposure limit is an order of magnitude below the point at which a room feels wrong.

Step 6, the bath was mixed before the trays were ready. Its clock started early. Finish the setting up with the bath covered, and record the extra minutes; a bath that stands open is a bath that has been gassing into the room for no purpose.

Step 7, the rinse was short and the print went straight from bleach to toner. Take the print out, rinse it properly, and expect the toner to have been acidified locally. If the bath has clouded or the smell has sharpened, leave the room and let the air change before you go back to it.

Step 10, you would rather keep the bath for next week. Do not. A standing sulphide bath is a standing hydrolysis equilibrium and a standing fog source, and the stock keeps far better than the working solution does.

Step 11, a funnel has been used for both. It is contaminated in the direction that matters. Rinse it into the sulphide container, retire it from the ferricyanide bottle, and label the replacement.

Step 13, a part-used container is the only one free. Read its label; if you cannot, it is unknown, and the unlabelled container procedure governs. Nobody plans to add an acid to a spent sulphide. They top up a bottle they did not read.

No through draught is available at all. Then this bench is not classified for the room. Tone outdoors on a board and water the print twice before bringing it back inside, which is the published fallback, or defer the session.

What to record

The stock: its strength, whether it was made or bought, its date and its label. The working bath: its dilution, the volume made, and the time it existed. The ventilation arrangement actually running. Then the three waste lines — container, contents, running volume, route, and the date the route was checked — and one sentence saying where the paper was kept while the bath was open.