How can 'undercut' or 'burned out' edges of a test piece in a film image usually be reduced?

The option that suggests masking the test piece as a method to reduce 'undercut' or 'burned out' edges in a film image is particularly relevant because masking can effectively restrict the exposure of certain areas of the film. This technique helps prevent overexposure in specific regions, which is often where undetected irregularities might appear due to excessive radiation. By carefully covering or masking the test piece, it is possible to create a more uniform exposure across the image, thereby minimizing the risk of artifacts associated with undetected edges.

In contrast, increasing the source activity typically results in a more intense radiation dose, which could exacerbate the problem of burned edges rather than mitigating it. Adjusting the exposure time is also less effective since longer exposure might lead to more pronounced burning out of the edges. Changing the film type could potentially affect the sensitivity or contrast of the film but doesn’t specifically address the uneven exposure leading to undercut or burned out edges. Thus, masking serves as a direct and effective solution to control overexposure in sensitive areas of the test piece.