قدرة الأفلام الملونة على البقاء دون تلف . كتاب التصوير الملون ،الكاتب عبد الفتاح رياض

The ability of color films to remain undamaged

Color films prepared for imaging by subtractive method do not have the same ability as black and white films to stay for a long time without deterioration.

Apart from the well-known results in “black and white” photography, such as a decrease in the speed of the sensitivity of the film if it is stored for a long time, or a change in the degree of contrast originally set for it, or a smear of fog, there is a new factor that interferes with the conditions of the length of time or poor storage of color film. This is because these films, as we know, consist of three layers whose sensitivity varies, so the length of storage does not affect them in one way. Rather, one of these layers may be affected to a greater or lesser extent than the other two, causing an imbalance in the colors of the image, which is something that cannot be fixed if the film is of the reverse type. And its importance is relatively less if the film is of the colored negative type (as it is permissible to fix it to some extent during the printing or enlarging stage). And given that it is possible - as a result of the long storage period - that the colors of the image become unbalanced and tend to turn red (usually), so some factories took care to increase the sensitivity of their products slightly towards blue, as a precaution to compensate for the lack of blue in the event that several months passed before using the film, and as an assumption from them These films will not reach the consumer except after a predetermined period of time, and thus the color balance will be correct when the films are used. The optimal methods for storing color film are no different from those suitable for films from

Black and white. In both cases, the storage place must be cool

Dry and away from chemical fumes and x-ray locations, as required

Always work on performing demonstration operations as soon as possible after imaging.

Supports

The color film support used according to the omission theory is often made of cellulose acetate that is non-flammable (cellulose actate safety base), and the materials prepared for printing or enlarging negative images (to obtain a positive image) are on a support of paper or opaque white plastic that is also a support For colored materials used to enlarge or print transparent images

Dimensions of colored films prepared for filming by extrusion: Negatives and colored reversals are manufactured as rolled films (965 cm) or 70 mm for cinematic purposes, 35 mm, 16 mm, 8 mm, and they are also made as flat films of different sizes. Likewise, the measurements of raw materials prepared for printing or color enlargement do not differ from the usual measurements in sensitive bromide papers suitable for “black and white” photography.