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Kodak color compensating Filters

It is possible to use any of these filters (which will be mentioned in Table No. 12 p. (81) either alone or in combination to perform the required degree of color correction. Using more than one filter in front of the photographic lens or in front of the magnifier lens will certainly affect the degree of clarity of the details Definiion

(1) We took this data from the following reference. A Kodak databook. 7.

Kodak color films, and it was stated in it for this purpose in particular, that Kodak factories have produced filters known as Kodak Color printing filters, and it is recommended to use them if we want to place the filter between the light source and the color negative, because in addition to its characteristics being suitable for this purpose, it is less expensive than others. .

CC means that the filter is Color Compensating

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Y means that this filter is yellow. It is noticeable in the group of these filters that the differences in intensity degrees (1) between each filter and the next = .O. Except for the first two candidates, the density difference between them = e. And . Just. This does not include in estimating the density values ​​(established next to the symbols of each filter) any consideration of the density of the gelatin in which the filter dye lies, or consideration of the density of the glass in which the gelatin may be coated.

They are placed as a result of light scattering, and therefore it is desirable to reduce the number of filters. The trade symbols of these filters indicate their properties. For example: CC - 20 Y denotes that:

It means that the density of this filter = 2 and 0

Thanks to the regularity in increasing the gradient of density values, it is easy to predict in advance the results that will result from the combination of more than one filter, and on page 81 there are tables for these filters.

ILFORD dilute Complementary Filters: They are filters belonging to the same species that we are dealing with, and their colors. Cyan, Magenta, and Yellow It is noticeable in the symbols denoting the colors of these filters that the manufacturer did not mention the color of the filter directly, but made the symbols indicative of the color of the rays absorbed by the filter. The Cyan filter is symbolized by the letters RA which stand for the words Red Absorbing, meaning the filter that absorbs red, and the Magenta filter is symbolized by the letters GA, which stands for the words Green Absorbing, meaning the filter that absorbs green.

(1) For information or information about the density of optical filters, please refer to the author's book, p. 154, first edition, published by the Anglo Egyptian Library - 165 Mohamed Farid Street, Cairo

BA and the yellow filter are denoted by the letters B A which denote both Blue Absorbing, i.e. the filter that absorbs blue.

These filters were given their numbers based on the equivalent neutral density, and the previous expression means that by combining filters of the three colors (cyan, magenta, and yellow) of equal density, their sum will equal the same density of a neutral color, meaning: Equivalent Neutral Density

Cyan filter 1.0 + magenta filter 10 + yellow filter 10 = Neutral density 1.0. = 1.0 BA 1.0 g A + 1.0 RA + The density of these filters is graduated regularly. And we get it in the form of squares of gelatin preserved between two sheets of glass.

Gevaert Filters: These filters are mainly designed to fix the colors of color positive images. The group of these filters consists of 33 filters, including 11 yellow filters, 11 purple filters, and 11 cyan filters. As we return to talking about these filters, we will expand on the study of printing and enlarging color images, so we will suffice here with this much about them. It is necessary to check from time to time the cleanliness of the gelatin filters and clean them with a soft brush or chamois leather prepared for this purpose.