Abstract: A film has a series of exposed and developed negatives. Each negative is scanned at a multiplicity of regions, and the densities of each region in the three primary colors are measured. A blue/red density differential is derived for each region by subtracting the red density of a respective region from its blue density. The neutral density of each region is calculated, and every region is assigned a coordinate on a plot of blue/red density differential versus neutral density. According to one embodiment, the blue/red density differential for each region having a neutral density equal to or greater than a limiting value is then subtracted from the blue/red density differential given by a characteristic curve for the film. The differences obtained in this manner are analyzed, at least for selected negatives, and the minimum difference for each selected negative is determined. The region corresponding to the minimum difference is that region of a negative having the maximum blue density.

Abstract: An exposed and developed strip of film has a series of frames which are to be copied. The strip is scanned at a multiplicity of regions to measure the transparencies in the three primary colors, and the most transparent region of the film strip is established. The neutral density of each region of a frame is calculated as are the density differences between the respective region and the most transparent region in the three primary colors. The color density differences for each region are plotted on a color density diagram having six equally spaced axes which radiate from a common origin. The origin is defined by the color densities of the most transparent region while the respective axes represent the three primary colors and the three complementary colors. The color density diagram is divided into four color segments. The density differences for each region are vectorially added in the color density diagram to generate a resultant vector.