agitate more, but not too much When pushing film several stops, traditional development can disproportionately increase highlights in high-contrast lighting. Stand Development can be used as a method of compensation. This is done by processing with a more diluted developer for a longer period of time, with little agitation.
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Nikon F100 | 50mm D | Ilford HP5 @ 1600
A film base (acetate or polyester) is the medium to which a photosensitive emulsion is applied. The gelatin emulsion contains silver halide crystals, namely silver bromide or silver bromochloroiodide. Upon exposure to photons of light, silver halide molecules split apart, producing separate atoms of silver. Chemical development converts the entire halide crystal to silver, even if only a few molecules were initially exposed. Larger silver halide crystals have a higher likelihood of being exposed and developed into silver, lending to a high sensitivity to light. The visual effect of this (seen in higher ISO film stocks) is a coarser grain structure. Film emulsions will have a distribution of grain sizes to control contrast curves. Crystal size varies from .02 - 2 microns, and can be applied as cubes, rectangles, tetradecahedrons, hexagons, or triangular and flat “T-grain” shapes.
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