![]() Tabular crystals also have less chance of absorbing high energy photons from ambient and cosmic radiation, giving longer shelf life without fogging. They also scatter the light less, giving sharper image but less gradation. Tabular crystals also better absorb sensitizing dyes. It is also more difficult to wash during the fixing stage. The more compact structure allows for thinner emulsion layers. The flat morphology allows better overlapping of the crystals, reducing intergranular space and giving more black for the same amount of silver. Tabular-grain film uses crystals of flat morphology, with width to thickness ratio of at least two, often much more. Fine grain better preserves details but requires more light. Large crystals will therefore give more sensitive film, for the price of being visibly grainier. There is a tradeoff between the crystal size and light sensitivity ( film speed) larger crystals have better chance to receive enough energy to flip them into developable state, as they have higher probability of receiving several photons needed for forming the Ag 4 clusters that start the autocatalytic process of development. The size and morphology of the silver halide grains play crucial role in the image characteristics and exposure behavior. It can be objectionably noticeable in an over-enlarged film photograph. It is an optical effect, the magnitude of which (amount of grain) depends on both the film stock and the definition at which it is observed. While film grain is a function of such particles (or dye clouds) it is not the same thing as such. Photomicrograph of grain of different photographic plates Film grain used for artistic effectįilm grain or film granularity is the random optical texture of processed photographic film due to the presence of small particles of a metallic silver, or dye clouds, developed from silver halide that have received enough photons. Optical texture of processed photographic film ![]()
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