محاليل الاظهار المذيبة لاملاح الفضة والمؤدية الى حبيبات دقيقة للغاية .

Third - Showing solutions that dissolve silver salts and lead to very fine granules:

These solutions are known as Super Fine Grain developers, and they are sometimes called Solvent developers, as another salt is added to the compounds that make up the solution. One of its properties is to dissolve part of the silver salts deposited in gelatin, which reduces the adhesion of small silver granules to each other, so larger granules are not formed. On the other hand, the dissolved silver salts are reduced and deposited on the surface of the film, in the same areas on which the image was formed.

Perhaps it has become clear from the previous explanation that there are two processes taking place simultaneously, namely:
(a) A chemical process, which is the reduction of silver salts to metallic silver.
(b) Two physical processes, which are the dissolution of the silver salt by the action of the solvent, then the silver is deposited on top of the image (which is the silver resulting from the reduction of the dissolved silver salt).

Although the first process is considered a chemical process, it has been ordered to name display in this case in excess of the name of “natural manifestation” Physical development to differentiate it from the usual methods of display in which the image is shown by purely quantitative means.

It is customary for the silver-dissolving salt to be among the following salts:
(a) Potassium Thiocyanate
(b) Ammonium Chloride
(H) Sodium Thiosulphate (Hypo), however, it is usually preferred to use the first salt due to the lack of haze on the image.

As the process of dissolving silver salts results in part of the underlying image being dissolved, so it is obvious that the use of these solutions will result in a decrease in the effective film speed of the films, which requires an increase in the exposure by a rate ranging from 50 to 100% than if we used solutions other display.

These solutions carry relatively large quantities of sodium sulfite salt (preservative). Therefore, it is able to remain without deterioration for a long time after its installation, and it follows that increasing the amount of sodium sulfite also helps the silver salt solvent in the solution.

The silver salts solvent display solutions are distinguished from the aforementioned low-voltage solutions in that they do not reduce the contrast and density, in addition to the accuracy. particle size.

The composition of some of these solutions is not very different from the composition of the show solutions with palmitol, hydroquinone and borax, except that they also contain a number of compounds that dissolve the aforementioned silver salts.

Hydroquinone may be added to other types of these solutions (such as Kodak Appearance Solution No. 2 20-DK).

Among those solutions that carry silver solvents are those prepared to work at very high temperatures, such as Gephardt antiseptic solution No. 223, and we will talk about the subject in detail later.