Elimination of copying light required for copying of colour originals - by obtaining colour density difference curves for each scanned area of film strip

摘要

The method is of determining, in each f the primary colours separately, the amt. of copying light required to be used during te copying of colour originals that are combined to form film strips. The film strips are scanned are by area photoelectrically, and separately in each of the primary colours and the results of the measurement are used to control the amts. of copying light. For each scanned area, a first difference between the density values of two primary colours is formed, and a second difference between the density values of one of those primary colours and the third primary colour is formed and the mean density of all three primary colours is formed. On the basis of, in each case, a number of orginals of a film, colour density difference curves over the mean density are generated from the assignment of the colour density difference values to the associated mean densities.