الفصل الثامن ، التصوير الملون .. كتاب فن التصوير الفوتوغرافي

Chapter VIII

color photography

With the advancement of the quality of color films, the popularity of color photography is increasing day by day among amateurs and professionals alike. Although the principle of color photography is the same as the principle of black and white photography, there are some fundamental differences in both types.

Remember, when we talked about colors, we said that the main colors are red, blue, and green, and that these colors are the basis for all other secondary colors. Thus, by coating the film with three sensitive emulsion layers of these main colors, the film can record all the colors of the spectrum... There remains one obstacle, which is that the colored film is sensitive to ultraviolet rays and to the blue end of the spectrum, just like its brother, the regular film. To overcome this obstacle, it is placed between two layers of The three layers of emulsion are a layer of yellow filter. However, the effect of blue and ultraviolet radiation remains completely uncontrolled, so a colorless filter is added to the previous filter and has the property of preventing ultraviolet rays from reaching sensitive film layers.

It is called the Haze Filter, as it is placed with the yellow filter between two of the three layers of emulsion to block the effect of radiation on the film. Thus, color film can record colors as they are in nature without any obstacles.

colored negative:

There are two basic types of color films 1 - negative 2 - reversal The performance of a colored negative is similar to the performance of a black and white negative to a large extent, where the colored negative records shades and areas of radiance like a normal negative, and the colors in it are reversed according to their complementary colors, so the blue sky looks yellow and the flowers The red ones appear dark blue, while the grass appears bluish red. For this reason, we cannot judge the quality of a colored negative before seeing it printed on paper, unlike the normal negative, which we can easily judge before printing. It is possible for you to show her colored elephant, but at the present time, the endorsement of the regular film must be mastered, whether in controlling the temperature or in the large number of necessary laboratory operations.

Accurate temperature control is essential in endorsing color films in order to maintain the health and balance of colors, in addition to the aforementioned reasons with regular films. Color film endorsement goes through six steps, as follows:

1- Color endorsement

2- Waqf bath

- Washing 4 - Color conversion bath (or bleaching) e - Fixation 6 - Washing

Endorsement of color films is an expensive process due to the high prices of color endorsement materials. Also, these materials have a very short shelf life. When printing final editions, each primary color is treated separately by balancing it using a filter for each special.
color . The difficulty here is that the required exposure time must be measured accurately. He also likes to measure the required exposure time with each filter, as each filter must pass through it an amount of light that does not exceed it in order to obtain an accurate balance in the colors of the final print. Exposing one incorrectly will lead to damage to the print

Permanently .

Perhaps you are now convinced of the reason for which we advised you to stay away from delving into the experience of developing color films. But this is not impossible for the hobbyist to develop color films. All he has to do is wait a little while until he masters the methods and techniques of the dark room before embarking on the colored acidification.