Negative film is stored in three emulsion layers (cyan, yellow, and magenta) on a base. Each layer has its own separate grain structure. What is Green on positive film is Magenta on negative film, and so on. Here are some graphics:
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Most of the grain is in the colour layers, and each layer has its own grain structure hence "varying degree of granularity". Additionally some layers are physically thicker than others. Here's a good view of a photographic film:
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Motion-picture film (negative):
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Positive motion-picture film:
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Dye layers are in a different order, due to using slower developing dyes/longer exposure.
If we split the positive digital image to RGB we get the emulation layers that would exist on the film negative:
Digital Blue -> Yellow Emulsion Layer
Digital Green -> Magenta Emulsion Layer
Digital Red -> Cyan Emulsion Layer
Therefore applying grain to blue applies it to yellow and so on. As already mentioned positive film has a finer grain than negative film.
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Most of the grain is in the colour layers, and each layer has its own grain structure hence "varying degree of granularity". Additionally some layers are physically thicker than others. Here's a good view of a photographic film:
🔍
Motion-picture film (negative):
🔍
🔍
Positive motion-picture film:
🔍
🔍
Dye layers are in a different order, due to using slower developing dyes/longer exposure.
Quote:Still don't get the negative/positive thing... don't we apply the grain plate (positive) to digital video (positive)? Why negative should be implied?
If we split the positive digital image to RGB we get the emulation layers that would exist on the film negative:
Digital Blue -> Yellow Emulsion Layer
Digital Green -> Magenta Emulsion Layer
Digital Red -> Cyan Emulsion Layer
Therefore applying grain to blue applies it to yellow and so on. As already mentioned positive film has a finer grain than negative film.