Curve analysis method in color printing

Claim 2

Method of determining the proper color balance in making a color print in color photography from a color negative including the steps of A. exposing a continuous density wedge or step tablet through the clear, unexposed and processed portion of a color negative photographic emulsion and a color compensating filter pack including a combination of at least one magenta filter selected from the group of magenta filters of 0.05, 0.10, 0.20, 0.30, 0.40, and 0.50 nominal density values and at least one cyan filter selected from the group of cyan filters of 0.05, 0.10, 0.20, 0.30, 0.40, and 0.50 nominal density value to make a test print, B. determining the densities to red, green, and blue light of the test print, C. plotting three discrete characteristic curves showing the relationship between the respective densities to red, green, and blue light and log exposure, D. determining from each of said curves the adjustment of the exposures to green and red light required to shift the green and red curves into coincidence with the blue curve and produce equal densities to red, green and blue light on the printing medium, E. converting the required amounts of exposure adjustment into equivalent amounts of density units for the magenta and cyan filters in the color compensating filter pack, F. determining the actual effective density for the magenta and cyan filters in the color compensating filter pack by determining the transmission densities to red, green, and blue light of magenta and cyan filters of 0.05, 0.10, 0.20, 0.30, 0.40, and 0.50 nominal density value, subtracting an amount of density equal to the blue density from each of the three densities and reducing the blue density to zero, G. preparing a TABLE having an ordinate and an abscissa axis, labelling each axis in intervals of 05 nominal density units from 0 to 100, said ordinate units referring to the nominal value of a color compensating magenta filter of a filter pack, said abscissa units referring to the nominal value of a color compensating cyan filter of a filter pack, ruling horizontal and vertical lines between said units to form a network of squares, each of said squares representing a particular magenta-cyan filter pack whose nominal values of magenta and cyan filtration corresponds to the respective ordinate and abscissa values intersecting at that square, H. totalling the equivalent densities to green light of all the filters in a magenta-cyan filter pack and totalling the equivalent densities to red light of all the filters in a magenta-cyan filter pack and entering these totals in the square of the TABLE associated with that filter pack such that the upper number in the square represents the equivalent density to green light and the lower number in the square represEnts the equivalent density to red light, I. locating the squre in the TABLE intersected by the color compensating filter pack of step (A), and J. adjusting the respective values in the square by the equivalent density units obtained in step (E) to obtain the equivalent densities of the filter pack which will balance the emulsion.

Claim 3

Method of determining the proper color balance in making a color print in color photography from a color negative including the steps of A. exposing a continuous wedge or step tablet each of three times through the clear, unexposed and processed portion of a color negative photographic emulsion with red, blue, and green light in succession in any order and in a manner such that definite amounts of respective red, blue, and green light energy reach the paper during each exposure to make a test print, B. determining the densities to red, green, and blue light of the test print, C. plotting three discrete characteristic curves showing the relationship between the respective densities to red, green, and blue light and log exposure, and D. calculating the adjustment to any two of the three exposures necessary to shift the curves into coincidence.