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Showing solutions that lead to fine granules
FINE GRAIN DEVELOPERS

The granules are metallic silver particles anchored in gelatin, resulting from the reduction of silver salt in the sensitive layer. You do not see these granules to the naked eye in the negative images, as you do not see them in the small positive image. Rather, they appear clear in the case of high magnification, which leads to a decrease in the artistic value of the image. The problem of grain size is an obstacle that prevents access to technically excellent negatives if the film is small in size, so the film factories tended to make fine grain films.
And since the size of the granules also depends on the composition of the exposure solution, therefore it was necessary to search for exposure solutions that lead to this purpose, and the need for them increased after the manufacture of small-sized cameras that carry films of small area. (35 ml or 16 ml or 8 ml).

Factors affecting particle size:
1- Film sensitivity speed: The higher the film or plate sensitivity speed. The size of the grains (Fig. 33), and accordingly we find that in exchange for what we gain from the speed of sensitivity, we lose a measure of artistic quality.
2- The duration of exposure: Increasing or decreasing the duration of exposure has a significant effect on the size of the grains. If we examined a section of a sensitive layer with a microscope before the silver salt was reduced, we would see it as small crystals. When the process of exposure begins, the process of reducing these crystals begins, turning them into metallic silver particles. If the period of manifestation increased, these particles or granules gradually united and connected to each other, and instead of each separate granule appearing, we find that these united granules formed one large granule, and this last granule united in turn with another large one forming a larger granule, and so on.
(Fig. 34). If we look at another fact, which is that by increasing the exposure time, the penetration of the developer solution into the sensitive gelatin layer increases, so it performs the same process in the lower layers of it.
(Fig. 35) We would have realized that the effect of the appearing solution may include most of the silver salt crystals in the gelatin layers, thus increasing the overall density of the general negative image, in addition to the enlargement of the granules that appear clearly in the image upon magnification. This also leads to a decrease in the sharpness of the image. On the contrary, the particle size decreases if the sensitive layer does not have enough time to complete the reduction. (The image in this case lacks contrast.)

2- Composition of the solution and appearance: We will talk about that in detail in the following.