EVALUATION OF EXPOSURE CHANGES REQUIRED DUE TO CHANGES IN THE EMULSION SPEED AND/OR CONTRAST RANGE OF PHOTOGRAPHIC FILM

摘要

1352123 Testing plaque for half-tone photography LITTLEJOHN GRAPHIC SYSTEMS Ltd 19 April 1971 [31 Oct 1969] 53534/69 Headings G2M and G2X A plaque for testing photographic film parameters comprises a backing sheet provided with a calibration grid, and one or more strips carried in fixed position by the backing sheet and providing a continuous smoothly changing tonal range of density values; two selected reference points, viz the high-light dot structure and shadow dot structure calibration points are indicated on the strip(s). The plaque may be of the transmission or reflective type. It may be used for evaluating exposure changes necessary to achieve consistent shadow and highlight dot structures due to film speed and/or contrast change of a film having a high contrast emulsion.