Exposure Chart
An exposure chart is a graph or table that gives the required exposure (mA-min for X-ray, Ci-min for gamma) versus material thickness for a specific film, density, kV, and source-to-film distance.
Definition
Exposure charts are developed empirically for each combination of radiation source, film, processing, and density. Inspectors use them to plan field exposures and minimize retakes.
Related terms
- Source-to-Film Distance (SFD) — Source-to-film distance (SFD), also called focus-film distance (FFD), is the geometric distance between the radiation source focal spot and the film, controlling geometric unsharpness and radiation intensity at the film.
- Radiographic Density — Radiographic density is the degree of film darkening, measured logarithmically with a densitometer, and is a key acceptance parameter ensuring the radiograph carries the full diagnostic information needed for interpretation.
- Half-Value Layer (HVL) — The half-value layer (HVL) is the thickness of a specified material required to reduce the intensity of a beam of radiation by half, used to characterize radiation penetration and design shielding.
More procedure terms
Contact Coupling · Immersion Testing · Wet Particle Method · Dry Particle Method · Fluorescent Particles · Visible Particles · Demagnetization · Multi-Directional Magnetization · Solvent-Removable Penetrant · Water-Washable Penetrant
Where this comes up in practice
Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.
Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A and ISO 9712, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.