Universal Acidic Rapid Fixative (Concentrate 1+4…1+9)

About Fixage

This concentrated, fast-acting acid fixer based on ammonium thiosulfate is diluted 5 times with water for processing photographic film and 5 or 10 times for processing photographic paper. It possesses all the beneficial properties of a classic acidic fixer and also offers a number of advantages: because it is highly concentrated, it can be stored for several months as a liquid concentrate, and the working solution can be prepared in less than a minute simply by diluting it with water. Ammonium thiosulfate washes out 3–5 times faster than the sodium thiosulfate found in classic fixers, and the acidic environment has less of an effect on the image’s fine grain, shadows, and tone. The speed of fixing is especially important when processing old, expired films with a weak or damaged emulsion, as well as films processed in color developers.

Character

An acid-based, fast-acting ammonium thiosulfate developer—it is washed out of the emulsion 3–5 times faster than sodium thiosulfate developers.

How to Prepare and Use

1. 1Preparing the concentrate: Pour about 600 mL of warm water (≈40 °C) into a 1-liter container and gradually dissolve the ammonium thiosulfate (500 g) in portions—a small yellow sulfur precipitate may form.
2. 2After the ammonium thiosulfate has completely dissolved, add sodium metabisulfite (45 g) and dissolve it completely.
3. 3Let the concentrate cool to room temperature, bring the volume up to 1 liter, and be sure to strain it.
4. 4The working solution is prepared by diluting the concentrate with room-temperature water—adding it in a thin stream while stirring until the desired volume is reached; there is no need to filter the working solution.
5. 5Standard dilution ratio of 1+4 (slightly acidic solution, pH ≈5.5): film development—1–4 minutes (more precisely, three times the bleaching time); photographic paper—1.5–4 minutes (baryta) or 1–3 minutes (polyethylene-coated), at 20 °C.
6. 6A 1+9 dilution is more suitable for photo paper: baryta paper—10–15 minutes, polyethylene-coated paper—7–12 minutes; film—about 7–10 minutes.
7. 7A 1+2 dilution produces an ultra-fast developer: film—0.5–2.0 minutes, baryta papers—1–3 minutes, polyethylene-coated papers—0.5–1.5 minutes; Do not exceed the optimal processing time you have determined—this may result in partial bleaching of the image.