Film contrast is the difference in density between areas in negatives. After
development, grains of silver halides remain in film but are redistributed to
create tonal areas of grey. These grey areas range from very dense to very
thin, depending on the brightness of the objects in the scene. The portions of
negatives where the most silver halides are affected are referred to as
highlights. The portions that are least affected are called shadows. Light
reflections from objects other than the brightest and the darkest are referred
to as midtones. The amount of metallic silver deposited in any portion of a
negative is referred to as density. Density describes the light-stopping ability
of a negative.
Emulsion latitude is the ability of a film to record a range of scene brightness
differences as density differences. Normal- and low-contrast emulsions
record a wide range of brightness. High-contrast films record a short range
of brightnesses and are considered to have a narrow latitude.
Exposure latitude is the amount of departure (increase or decrease) from the
ideal exposure setting the film will allow while still producing negatives of
Emulsion definition is the ability of films to produce clear, sharp images.
Emulsion definition includes graininess, resolving power (resolution), and
acutance (the ability to produce sharp edges).
GRAININESS: Graininess is a speckled, mottled, or granular appearance on
the surface of negatives that is magnified in prints. The amount of apparent
grain depends on the size of silver halides, the exposure the film received,
and the clumping of the silver grains during development. Extreme
graininess is called reticulation and may be used creatively to add interest to
RESOLUTION: Resolution is the ability of films to record fine detail. The
resolution or resolving power is expressed as line pairs per millimeter. As
negatives are enlarged, resolution lessens and grain increases. This softening
of the image becomes most apparent when cropping 35mm negatives and
enlarging them in print.
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