Improve your image - 6: films and processing

Abstract

SUMMARY • The photograph is created by the deposition of metallic silver in a pattern on film. This is caused by the ionisation of silver halide grains on the film and their subsequent development. • Chemical processing converts the latent image into a visible image and fixes it for viewing purposes. • Processing is an exact laboratory reaction that should be performed with precision in an appropriate environment. It is temperature and time dependent and relies on the use of fresh chemical solutions that have been accurately prepared. • Most radiographic faults in veterinary practice happen in the darkroom and many relate to the processing reaction itself. The most common problem is underdevelopment and this may be the result of inadequate temperature, too short a reaction time or old chemicals. • Film and chemistry should be compatible and the manufacturer's instructions followed precisely. • Automatic processors may seem expensive, but they produce a consistent result in a fraction of the time. They are cost effective in all but the smallest of practices. Efficient production will facilitate greater radiographic volume, which adds to its cost effectiveness.