محاليل الإظهار التي تزيد التباين .. كتاب التحميض والطبع والتكبير

Show solutions that increase contrast
CONTRAST DEVELOPERS

These solutions are divided into the following two sections.

(a) Presentation solutions that increase contrast to its maximum degree, and this case is required by photographic transfers of originals written, for example, in black ink on white paper, such as photocopying documents or filming movie titles...etc.

(b) Brightening solutions that increase the contrast by an average amount, so that the color values ​​in the image exceed their value in nature or the original. For example, in the case of showing photographic images necessary for printing and press purposes, and to increase the contrast to its maximum levels, sometimes brightening solutions are used consisting of two parts that carry one They are the reducing agent, preservative and inhibitor. As for the second part, it contains the alkaline substance, which may be caustic soda or caustic potash, and the parts are only mixed. Immediately prior to use, because they quickly deteriorate if left after mixing. An example of this is the presenting solution - (on the next page). The solution may be from one part only and must be used immediately after its composition, such as the presenting solution. The following are examples of the composition of solutions that increase contrast: