An Investigation using CC filtration to predict dot size changes in order to achieve desirable color balance

The purpose of this study was to investigate a method of color evaluation which can be used by the customer when reviewing color proofs. The method being proposed here incorporates the use of color compensating (CC) filters when evaluating proofs where an overall color correction is necessary. The color balance among pictures that are to appear in close proximity to each other is a major consideration in publication printing as well as certain aspects of commercial printing. There is a need for an effective means of obtaining good reproductions of individual subjects while maintaining a visual consistency between them. In such cases a deliberate departure from normal color balance for a particular image may be desired. By using CC filtration, the customer is able to evaluate a proof and specify the changes in color balance by physical means. However, once a filter is specified as giving the desired visual effect, it must be quantified as to how much and what kind of changes on film are necessary to achieve the correct result. This study attempted to determine if it was possible to quantify filter selections by means of dry dot etching. Manipulations in color balance on film were made to three levels of dot change in an increasing direction and three levels of change in a decreasing direction. These six levels (A, B, C, -A, -B, -C) were made in the cyan printer of one separation, the magenta of another, and the yellow printer of a third. This gave a total of eighteen samples being produced. The dot size changes were accomplished by dry dot etching overall with the assistance of the Kodak Dry Dot Etching System. A panel of judges was used to determine whether or not there is a correlation between CC filtration and the amount of dot change made to a separation in order to achieve the desired visual match between the reference proof and the sample proof. The judges were given the reference proof and one sample at a time to view. The panel attempted to make a visual match in one of two ways: to choose a filter that would allow the reference proof to match the altered proof, or to choose a filter to remove the color cast from the altered proof in order to match the reference proof. The evaluation procedure was followed for all eighteen samples. The correlation coefficients were calculated for each of the three colors changed. The correlation proved to be quite high thereby substantiating the objectives of the filter evaluation method. However upon calculating and plotting the standard deviations of the judges\u27 results, the filter evaluation method proved to be useful when correcting overall color balance only within a certain amount of dot change. The objective of this method was to apply the filter evaluation technique in order to minimize the trial and error approach involved in making color corrections. When applied, this method could result in less waste of labor and materials which in turn results in higher productivity. In the end the separation/correction procedure becomes more cost effective