Abstract: In a settable matrix photographic color printer, Neutral, Green-chromaticity, and Illuminant-chromaticity correction levels and associated color rotations are adjusted by: transforming the printer correction matrix from a Red, Green, Blue coordinate system to a Neutral, Green-chromaticity, Illuminant-chromaticity coordinate system whereby the diagonal elements of the transformed matrix represent the Neutral, Green-chromaticity, and Illuminant-chromaticity correction levels, and the off-diagonal elements of the matrix represent color rotations; changing the value of the elements of the transformed matrix as desired; and transforming the thus adjusted matrix back into the Red, Green, Blue color coordinate system.

Abstract: An exposure control apparatus for use in a photographic printer determines a color correction factor based on color densities of an original. This correction factor is then utilized in customizing a correction matrix which converts signals representing density levels to signals for use in controlling exposures.

Abstract: An exposure control apparatus for use in photographic printers assigns the originals which are received for printing to groups or sets, for example, according to filmstrip membership, and bases the printing exposure for each such original, at least in part, on characteristics determined for a corresponding set taken as a whole. In a presently preferred apparatus, the exposures for individual frames from a filmstrip are controlled in accordance with the average optical density for the overall filmstrip in selectively weighted combination with individual frame, optical density characteristics.