إعداد الطبعة الأولى المعدة لاختبار الألوان وتقدير مدة التعريض الصحيحة .

Preparing the first print prepared for color testing and estimating the correct exposure time:

Sudah. As we know about black and white photography, it is necessary first, when printing or enlarging, to determine the required exposure time, and this may be done by any of the known methods (1) regarding photography in the context of exponential white photography, and then comes the stage of collecting the basic correction numbers necessary for each of the Positive paper or film (which is attached to the paper envelope) with the specific correction numbers for the printing or enlarging device that were previously calculated above), and thus it remains only to decide the correction numbers for the negative image, and this requires preliminary experiments after which the colors of the image are examined to estimate what they are. of casts, then removed according to the methods we have previously mentioned (p. 306). This negative correction numbers do not depend on the mere manufacture of the negative sensitive film and the correctness of the balance (1). These methods were mentioned in the book Developing, printing and enlarging (p. 263) in the first edition of the author:
Its colors, but also depend on other considerations, namely (a) the colors of the rays of the light source that were used at the time of photography, (b) and the colors of the medium surrounding the photographed subjects, (h) it also depends on how the processes of displaying the negative image were carried out and the circumstances surrounding it. In Figure 69 See a simplified way to shorten the time required to make test prints of a set of color images.

4

(fig. 69)

A simple way to shorten the time required for test prints

To shorten the time needed to prepare the first colored prints prepared for the initial color test. If the negatives are small in texture, a number of negatives can be collected on the aforementioned sensitive paper holder. It is twisted (in the figure) and a sheet of sensitive paper is placed below the negatives, and after turning off the lamp, the rays emitted from A magnifier lens (indicated by a b in the figure) is the light source needed for the exposure. The exposure time is estimated using an electric clock (indicated by a letter). It goes without saying that for the nursing of all images to be correct, it is required that the density of all negatives be very close. We took this form quoting the following reference: -

jack. H. Coote - Color Prints-Revised Edition, 1963. P. 192
Positive correction numbers are forcibly changed in stages as a result of printing or enlarging an image: It is likely that the amount of colored sensitive paper from the envelope will run out, and it is necessary to complete printing or enlarging the images on colored paper from another envelope in which the positive correction numbers differ from the correction numbers of the first type of paper. . Here, the new correction is made according to the following example:

Example 1: 20 Assuming that the group of correction numbers that were used before changing the paper and that the positive correction numbers on the paper that ran out = 20, then the difference between the previous two groups of images on the new paper is 30 -

If the correction numbers for the new paper = 40, then the set of correction numbers needed to print or enlarge -