What is the term used to describe the quantitative measure of film blackening?

The term that refers to the quantitative measure of film blackening is photographic density. Photographic density is a measure of the degree of blackening on the film after it has been exposed to radiation and processed. It is expressed in logarithmic terms, typically using a scale that quantifies the amount of light that passes through the film. The increased density indicates more radiation exposure, resulting in a darker film, which plays a crucial role in interpreting the radiographs produced during radiographic testing.

Understanding photographic density is essential in radiographic testing because it allows technicians to assess the quality of the film and the adequacy of the exposure. A higher photographic density means a stronger image, which aids in identifying defects or irregularities in the material being tested. This understanding is foundational in ensuring accurate interpretations in non-destructive testing practices.