Overview
ISO 11699-2:2018 - "Non-destructive testing - Industrial radiographic films - Part 2: Control of film processing by means of reference values" defines a practical procedure for controlling film processing systems used in industrial radiography. The standard requires the use of pre-exposed film strips with certified reference values so users can verify processing system performance and demonstrate compliance with a chosen film system classification.
Keywords: ISO 11699-2, industrial radiographic films, non-destructive testing, film processing control, pre-exposed film strips, reference values.
Key Topics
- Pre-exposed film strip manufacture
- Minimum exposed area: 15 mm × 100 mm.
- Strips contain at least ten optical-density steps (density increments ≈ 0.3) plus a blank area for base-plus-fog measurement.
- Exposure typically uses a step wedge arrangement; precautions against scattered radiation are required.
- Reference values and indices
- Users derive a reference speed index (S_r) and reference contrast index (C_r) from specified steps (step X near net density D ≈ 2 and step X+4).
- Reference values are obtained by processing at least five certified strips; resulting densities must have variance ≤ ±0.1.
- S_r and C_r are averaged and rounded to two decimals.
- Certification and documentation
- Pre-exposed strips must be supplied with a certificate listing processing descriptions (processor, chemistry, cycle, temperatures), brand/type, reference indices and step numbers, and reference optical densities.
- Storage conditions and expiry date must be stated.
- User verification and processing conditions
- Procedures for automatic and manual processing, including start-up conditioning and chemical control.
- Allowance for small adjustment (developer temperature ±2 K) at installation to meet reference values.
- Guidance for mixed systems (film from one manufacturer, chemistry/processor from another) and how users can establish equivalent conformity.
- Measurement and control
- Densitometer calibration, parameters for evaluating processing (speed, contrast, fixing/washing control), checking intervals, and test-report requirements.
Applications
- Quality control in industrial radiography labs to ensure consistent image density and contrast.
- Routine verification by NDT technicians, radiographers, and QA managers responsible for film-based radiography.
- Film manufacturers and chemical suppliers for producing certified pre-exposed strips and supporting customers’ compliance.
- Regulatory bodies and inspection authorities requiring documented evidence of processing-system performance.
Related Standards
- ISO 11699-1 - Classification of film systems for industrial radiography.
- ISO 18901 - Processed silver‑gelatin‑type black‑and‑white films - stability specifications.
- ISO 11699 series (other parts) for broader guidance on industrial radiographic films.
Use ISO 11699-2:2018 as the operational reference when implementing a documented, repeatable method to control film processing and demonstrate compliance with film system classifications in NDT radiography.
Open preview (PDF)Non-destructive testing — Industrial radiographic films — Part 2: Control of film processing by means of reference values