الخامات الموجبة الملونة المتعددة الطبقات .. كتاب التصوير الملون ، عبد الفتاح رياض

Multilayer colored cationic materials

Subtractive positive materials

Spectral sensitivity curves. Under the word “raw materials” all of the sensitive paper and films prepared for printing negative images are included in order to obtain positive images. Positive raw materials may differ from negative ones with regard to their tonal gradation and their spectral sensitivity curve.

As for the arrangement of the three sensitive layers in the colored positive films, they are either consistent with the arrangement of the aforementioned layers on p. 143, 144, and colored figures 57, 58 (p.

A pillar, then above it. (b) A layer that is sensitive to blue rays (and has yellow color problems) (7) then a layer that is sensitive to green rays (and has scarlet color problems) (d) then a top layer that is sensitive to red rays (and has cyan color problems). He neglected to put the yellow filter (which absorbs blue rays), but the factories replace this filter by making the sensitive layer to blue rays very sensitive to these rays, while making the other two layers (sensitive to red and green rays) weakly sensitive to blue rays as much as possible.

Here we may wonder. The wisdom is to deviate from the usual rule in arranging sensitive layers (according to what is shown in Figure 46 p. 144), and in response to that we say that it has been proven that placing the two upper layers sensitive to red and green rays and making the lower layer sensitive to blue rays increases the sharpness of the image ( Sharpness), which is especially necessary for color positive films, as they get very large on the display screen. We will come back to explain the arrangement of sensitive layers on colored photographic prepared paper when we talk about “printing and enlarging colored images.” about it