Measurement of Dimensional Changes of Graphic Arts Photographic Film.

Improvements in recent years in the dimensional stability of graphic arts photographic film have resulted in the need for a better measuring technique. A moirepattern method has been developed which involves exposing the film to a 50% halftone glass master. After processing, the film and glass master are re-registered and size changes determined from the resulting moirepattern. This method is very precise and can be used for evaluation of film performance under practical conditions. It also enables measurements to be made in different directions in the plane of the film.