Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

The use of lead screens has no significant effect on film graininess. However,
graininess is affected by processing conditions, being directly related to the
degree of development. For instance, if development time is increased for the
purpose of increasing film speed, the graininess of the resulting image is
likewise increased. Conversely, a developer or developing technique that
results in an appreciable decrease in graininess will also cause an
appreciable loss in film speed. However, adjustments made in development
technique to compensate for changes in temperature or activity of a
developer will have little effect on graininess. Such adjustments are made to
achieve the same degree of development as would be obtained in the fresh
developer at a standard processing temperature, and therefore the graininess
of the film will be essentially unaffected. Another source of the irregular
density in uniformly exposed areas is the screen mottle encountered in
radiography with the fluorescent screens. The screen mottle increases
markedly as hardness of the radiation increases. This is one of the factors
that limits the use of fluorescent screens at high voltage and with gamma rays.
Charlie Chong/ Fion Zhang
Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980