Test film for offset process - has different thickness lines with set gray level and spacing

摘要

A test film for checking an offset process has a series of wide lines spaced by large amounts and narrower lines at closer spacings. The thick lines have a set gray level which is checked with a gray scale chart. The test film is inserted in different places on the document table for checking the operation of the machine. The test chart is checked with a min. of training. It provides a gray level check as well as a resolution check. The spaced lines can be replaced by a set of concentric rings and shapes more readily positioned in small areas of the document support.