Photographic printer with automatic slope compensation

摘要

The photographic printer of the present invention automatically derives and stores slope compensation factors which are used in subsequent printing to compensate for exposure. Reference or slope center values are stored for a reference negative and prints of various negatives are made. A print which requires correction is selected from the test prints which have been made, and the desired density corrections for that print are supplied to the printer. The density values of the negative from which the print was made are measured, and slope compensation factors are derived from the slope center values, the desired density corrections, and the measured density values. Exposures in subsequent printings are compensated based upon these derived slope compensation factors.