Abstract: A method of determining exposure time for a photographic printer on the basis of a cubic function is provided. A plurality of test printings are conducted by using different print magnifications, in such a manner as to obtain the same density of test prints. Exposure times T during test printings are measured in correspondence with the print magnifications m. On the basis of the print magnifications m and the exposure times T, the exposure time is expressed as a cubic function (am.sup.3 +bm.sup.2 +cm+d) of the print magnification. An exposure time for actual printing is determined on the basis of the above-mentioned cubic function, and printing is effected.

Abstract: A photographic printing system equipped with an analyzer for displaying on a CRT an image equivalent to that of the print and a plurality of enlargers for performing printing based upon data obtained by means of the analyzer. In the analyzer, the data displayed on the CRT are transduced into printing condition data for each enlarger and stored on a storage medium for each of the enlargers so that an optimum print may be obtained at each of the enlargers. The enlargers select the corresponding printing condition data from the storage medium and perform printing. The data displayed on the CRT are transduced into the printing condition data for each of the enlargers, so that the same print can be obtained even when printing is performed based upon the same data displayed on the CRT using a plurality of enlargers with different exposure systems.

Abstract: An offset drift correction method for use in in a color film inspection apparatus includes the steps of; measuring the changes of various amounts of light at intervals of a predetermined amount of light as density signals by using a green standardized logarithmic-transforming curve; providing table data by shifting the green standardized logarithmic-transforming curve as to inputs in such a way that the changes become equal to one another; writing the table data in a green look-up table; measuring input signals for red and blue at intervals of the predetermined amount of light; and substituting the measured inputs with the table data of the shifted green standardized logarithmic-transforming curve at corresponding amounts of light.