Overview
ISO 10349-10:1992 specifies a comparative chemical test method for the determination of sulfide content in photographic‑grade chemicals. The standard is part of the ISO 10349 series on photographic‑grade chemical test methods and defines a simple, visual, color‑comparison procedure using Nessler colour‑comparison cylinders, a prepared sulfide standard, and an alkaline lead reagent. The method is intended for routine quality control of chemicals used in photographic processing and related materials.
Key topics and requirements
- Scope: A general test method to determine sulfide content in photographic‑grade chemicals (ISO 10349 series context).
- Sample and reagents:
- Test portion: 2.0 g ± 0.1 g dissolved in 25 ml water.
- Sulfide standard: prepared from sodium sulfide nonahydrate (procedure yields a labeled standard; the document specifies a standard concentration of 0.001 mg S/ml).
- Alkaline lead solution: prepared by combining sodium hydroxide solution with lead acetate solution until a precipitate redissolves, then adding a small excess (lead reagent is used with care because of health hazards).
- Apparatus: Two matched Nessler colour‑comparison cylinders (50 ml capacity each).
- Procedure:
- Transfer the dissolved sample into one Nessler cylinder.
- Pipette the specified volume of sulfide standard into the matched cylinder (volumes depend on the test limit; consult the standard’s table for exact volumes).
- Add 2 ml alkaline lead solution to each cylinder, make up to the 50 ml mark, mix thoroughly.
- Compare colour and clarity of the two solutions visually. Any darkening in the test solution must not exceed that of the treated sulfide standard.
- Safety: Lead acetate is identified as a potential carcinogen and reproductive hazard. Follow ISO 10349‑1 for general hazard guidance and laboratory safety.
Applications and users
- Used for quality control of photographic‑grade chemicals (suppliers and manufacturers).
- Suitable for chemical analysis laboratories performing incoming inspection or routine batch testing of photographic reagents.
- Useful to conservators and analytical chemists verifying impurity levels that can affect photographic processing quality.
- Typical users: laboratory technicians, QC managers, standards compliance personnel, and technical auditors in photographic chemical production.
Related standards
- ISO 10349‑1:1992 - Photography - Photographic‑grade chemicals - Test methods - Part 1: General (hazard codes, glassware and general requirements).
- Other parts of ISO 10349 address insolubles, heavy metals, halides, alkalinity, and related chemical tests.
Keywords: ISO 10349-10, sulfide content determination, photographic‑grade chemicals, Nessler colour‑comparison, alkaline lead reagent, sulfide standard, photography chemical QC.
Open preview (PDF)Photography — Photographic-grade chemicals — Test methods — Part 10: Determination of sulfide content
