Spectral Sensitivity of Offset Printing Mates.

Experiments were conducted, to determine the spectral sensitivity for four presensitized offset printing plates. The experiments consisted of exposing the printing plates to known wavelengths and exposure. The plates' spectral sensitivity is determined by measuring the absolute quantities of monochromatic energy which produced a given density on the plate material, after development. The plates' spectral sensitivity is determined by measuring the absolute quantities of monochromatic energy which produced a given density on the plate material, after development. Generally, two image forming systems were found. The first had a peak sensitivity at 365 nanometers, and the other at 405 nanometers. At wavelengths of maximum sensitivity, the energy requirements were found to be 4 to 17 mj/cm2.