What does a relatively lesser tissue density produce on a film?

A film shows varying degrees of image density based on the different tissue densities it interacts with during exposure. When tissue density is relatively lesser, it means that the tissue allows more x-ray penetration compared to denser tissues. This increased penetration results in less attenuation of the x-ray beam, leading to more exposure of the film in those areas.

As a result, the film appears darker in regions where the x-rays have passed through less dense tissue. This is because exposed film darkens when it undergoes development, resulting in areas corresponding to lesser tissue density appearing darker on the film. This principle is fundamental in radiography and dosimetry, as it allows medical professionals to differentiate between various tissues based on their radiation absorption characteristics.