ISO 10349-4:1992

Overview

ISO 10349-4:1992 - Photography - Photographic-grade chemicals - Test methods - Part 4: Determination of residue after ignition - describes a standardized laboratory procedure to determine the non‑volatile residue (ash) left after ignition of a photographic‑grade chemical. The method is intended for quality control and as a preparative step for subsequent tests (for example, heavy metals and iron). It defines apparatus, sampling references, basic procedure steps, calculation principles and reporting requirements.

Key topics and requirements

• Scope: General test method for determination of residue after ignition for photographic‑grade chemicals.
• Apparatus:
  • Ignition crucible: porcelain, alumina, platinum or quartz, capacity ≥ 100 ml.
  • Muffle furnace: capable of maintaining temperatures up to 600 °C.
  • Desiccator: with suitable desiccant for cooling to room temperature.
• Sampling & references: Sampling is done in accordance with ISO 10349‑1 (General). Hazard guidance and reagent/glassware requirements are also referenced to ISO 10349‑1.
• Procedure (summary):
  • Weigh the test portion to the nearest 0.01 g and place it in a prepared ignition crucible.
  • Heat over a low flame to drive off volatile matter.
  • Incinerate the sample in a muffle furnace for the specified time/temperature.
  • Cool to room temperature in a desiccator and reweigh to the required precision (procedure specifies reweighing to 0.001 g where applicable).
• Calculation: Residue is reported as a percentage by mass, based on the masses of the test portion, the empty crucible, and the crucible plus residue after ignition.
• Reporting: The test report must specify the method used, the numerical result, any optional operating details, and any incidents affecting the result, plus full sample identification.

Applications and who uses it

• Quality control laboratories in manufacturers of photographic‑grade chemicals use ISO 10349‑4:1992 to verify purity and consistency.
• Analytical and testing laboratories use the residue after ignition as an input for further analyses (e.g., heavy metals, iron content).
• Procurement and compliance officers rely on standardized test results when specifying or accepting photographic chemicals.
• Research groups working with photographic materials who require reproducible, comparable ash/residue data.

Related standards

• ISO 10349‑1:1992 - Photography - Photographic‑grade chemicals - Test methods - Part 1: General (sampling, hazards, reagents, and notation for drying).
• Other parts of ISO 10349 series cover insoluble matter, heavy metals, halides, alkalinity, volatile matter, sulfide content, specific gravity, density, and related test methods.

Keywords: ISO 10349-4:1992, residue after ignition, photographic-grade chemicals, ignition crucible, muffle furnace, desiccator, test method, photography quality control.