Integrating densitometer

Claim 1

An integrating densitometer for evaluating a reference and a photographically processed test print made by a photographing printing system, prior to making another print comprising: a light source; light sensor means; a stage for supporting an image of a reference or the test print as illuminated by said light source wherein said sensor means responds to light rays along a light path as influenced by the image at said stage; a plurality of color filter means movable selectively into the light path between said light sensor means, and said stage for ascertaining at least trichromatic quantity and quality values of the image at said stage; circuitry including means for establishing electrical reference values for the quantity and quality of light impinging on the reference image at said stage for evaluation of said light sensor means, the electrical reference values representing the density and/or trichromatic quantity and quality of the light from the reference image at said stage; and density control means for biasing simultaneously said electrical reference establishing means to shift said trichromatic values proportionately as required to obtain equalization of the density value upon comparison of the reference and test print images wherein the differences in the density and/or the trichromatic values of the reference and the test print are introduced into the photographic printing system to generate another print.