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Glossary
D
Daguerreotype:
the first practical photographic process, invented by Daguerre and
described by him in 1839. The process produced a positive image
formed by mercury vapor on a metal place coated with silver iodide.
Daylight
film: color film that is
balanced to produce accurate color renditions when the light source
illuminating the photographed scene has a color temperature of about
5500K, such as in midday sunlight or with electronic flash or blue
flashbulb
Dense:
describes a negative or an area of a negative in which a large amount
of silver has been deposited. Dense negatives transmit relatively
little light. Opposite: thin
Densitometer:
an instrument that measures the darkness or density of a negative
or print
Density:
the relative amount of silver present in various areas of film or
paper after exposure or development; therefore, the darkness of
a photographic print or the light-stopping ability of a negative
or transparency
Depth
of field: the area between
the nearest and farthest points from the camera that is acceptably
sharp in an image
Developer:
a chemical solution that changes the invisible, latent image produced
during exposure into a visible one
Diffuse:
scattered, not all coming from the same direction; i.e., sunlight
on a cloudy day
DIN:
a numerical rating used in Europe to describe the sensitivity of
film to light. The DIN rating increased by 3 as the sensitivity
of the film doubles
Dodge:
to lighten an area of a print by shading it during part of the printing
exposure
Dry
down: to become very slightly
darker & less contrasty, as most photo printing papers do when
dried after processing
Dry
mount: to attach a print
to another surface, usually mat board, by placing a sheet of dry-mount
adhesive between the print & the mounting surface. This “sandwich”
is placed in a heated mounting press and the adhesive melted. Pressure
sensitive adhesive that doesn’t require heat may also be used.
DX
coding: a checkered or
bar code on some film cassettes for electronic scanning of information
by automatic cameras and processing equipment that tells the speed
of the film and number of exposures
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