| 摘要 |
A photometric device for measuring the differences in primary color optical densities between spectrally neutral areas of a standard photographic color negative and a color negative to be printed. These density measurements determine the densities of proper color compensating filters required for photographic color printing. Memory voltages are provided which are proportional to the intensities of the primary colors transmitted through a spectrally neutral area of a standard color negative and standard filter pack. Light, transmitted through a spectrally neutral area of a color negative to be printed and sequentially selected primary color filters, is incident on a photodetector. The resulting photocurrents sequentially generate voltages across an amplifier variable load resistor, which is adjusted for each of the primary colors so that the voltage developed across it is equal to the corresponding memory voltage as indicated by a null detector. The variable load resistor is calibrated to read optical density and indicates the proper filter compensation for the photographic color negative to be printed.
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