ISO 10349-12:1992

Overview

ISO 10349-12:1992 specifies a standardized method for the determination of density of solutions used in photographic processing. The method requires measurements at thermal equilibrium in a constant-temperature water-bath set at 25 °C, using a density meter capable of reading to 0.001 units. This procedure supports consistent quality control and reliable characterization of photographic-grade chemicals.

Key Topics

• Scope: General test method for density measurement of photographic processing solutions.
• Apparatus:
  • Density meter with resolution of 0.001 units.
  • Constant-temperature water-bath with circulation and heating, maintained at 25 °C (bath uniformity recommended to ±0.05 °C).
• Sampling and test portion: A test portion of 100 ml of the sample is placed in a clean, dry container and immersed in the water-bath until thermal equilibrium with the bath is reached.
• Calibration: Calibrate the density meter according to the manufacturer’s instructions; calibration should be checked against deionized or distilled water at 25 °C using a reference relative density value of 0.99704.
• Measurement procedure: After thermal equilibrium, determine the density using the density meter following the manufacturer’s operating instructions.
• Hazards: See ISO 10349-1 for general hazard warnings related to handling photographic chemicals and safe laboratory practice.
• Test report: The report shall identify the sample, state the method used, and give the measured density. Include any optional operating details or incidents that could affect the result.

Applications

This part of ISO 10349 is practical for organizations that require reproducible density data for photographic solutions, including:

• Quality control in chemical manufacturing and photographic processing labs.
• Incoming inspection of reagent lots to confirm compliance with specification.
• Process control where solution concentration correlates with density.
• R&D and formulation work for photographic-grade chemicals where density is a critical parameter.

Using a standardized method reduces variability between laboratories and supports traceable, comparable results across production, testing, and regulatory contexts.

Related Standards

• ISO 10349 series - Photography - Photographic-grade chemicals - Test methods. Key related parts include:
  • Part 1: General (sampling, hazards, general requirements).
  • Other parts in the series cover insoluble matter, residue after ignition, heavy metals, halide content, alkalinity/acidity, volatile matter, sulfide content and related test methods.

For procedural details not covered in this part (for example, hazard control and sampling protocols), refer to ISO 10349-1 and the manufacturer’s instrument manuals. Adhering to ISO 10349-12:1992 ensures consistent density measurement practice for photographic processing solutions.