Image quality is a prerequisite for useful interpretation, but no single check proves that a component is acceptable. A radiograph should be reviewed against the technique and written procedure that apply to the examination.
What image quality review looks for
A reviewer confirms that the radiograph is identifiable and covers the required area, then checks the image characteristics required by the procedure. These may include optical density, contrast, sharpness, scatter control and visibility of the specified image quality indicator (IQI). The applicable standard defines the required method and limits; do not substitute a memorized value from another job.
What an IQI tells you
An IQI (also called a penetrameter in some codes) is used to demonstrate radiographic image quality or sensitivity under the stated technique. Its type, material, size and placement matter. Visibility of the required wire or hole is evidence about the radiographic setup and image—not a direct measurement of the size of a flaw, and not an acceptance decision for the weld or part.
Look for artifacts before interpreting
Handling marks, pressure marks, static, dirt, scratches, screen contact problems, chemical stains, fogging and light leaks can create features that resemble or obscure indications. Check the film and processing record when an unusual feature appears. Compare with adjacent exposures, component geometry and other relevant views where the procedure allows. If image quality is inadequate, follow the approved disposition and re-exposure rules rather than trying to interpret beyond the available evidence.
Keep the review sequence consistent
- Verify film identification, location and required coverage.
- Check the specified IQI result and other technique indicators.
- Assess image condition and note any artifacts or limitations.
- Interpret indications only within the examiner’s qualification and authorization.
- Evaluate against the job’s specified acceptance criteria and document the result.
ISO 17636-1:2022 addresses film radiographic technique and image-quality requirements for welded joints. It does not provide acceptance levels; those must come from the applicable evaluation standard, contract and approved procedure.