What is the required density range for the radiograph film?

• A. Density range from 1.0 to 2.5
• B. Density range from 1.8 to 3.5
• C. Density range from 2.0 to 4.0
• D. Density range from 1.5 to 3.0

Answer: (B)

In radiographic welding inspection, the film’s optical density must fall within a defined range to ensure enough contrast while keeping details visible. The standard range here is 1.8 to 3.5. This level of darkness provides good differential contrast so defects inside the weld and heat-affected zone can be seen under normal viewing conditions.

If the density is too low (below 1.8), the image is too light and lacks contrast, making small flaws hard to detect. If the density is too high (above 3.5), the image becomes too dark, washing out details and potentially hiding defects. This range helps maintain consistency across radiographs, with density controlled through exposure, filtration, and film processing.