ISO 10349-10:1992

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.