color: A way to produce
colors of light by mixing light of the three additive primary colors
- red, green, and blue. Varying proportions of the additive primaries
can be combined to create light of all other colors, including white,
which is a mixture of all wavelengths.
Egg white; used in early photographic emulsions as a coating for
papers. Also used for glass plates.
a substance with a pH above 7. Developers are usually alkaline
light: see available
a collodion wet-plate process in which the emulsion was coated on
a glass plate. The negative image produced was visible as a positive
image when the glass was backed with a dark material.
the size of the lens opening through which light passes. The relative
aperture is measured as the focal length of the lens divided by
the diameter of the aperture; this is expresses as an f-number:
f/8, f/11, etc.
a mode of automatic exposure in which the photographer selects the
aperture and the camera sets the shutter speed that will produce
the correct exposure.
of film and paper designed to protect the print or negative as much
as possible from premature deterioration caused by chemical reactions.
light: light from an electric
lamp, a flash bulb, or electronic flash. Often describes lights
the photographer has set up to illuminate a scene
focus: a system by which
the camera adjusts its lens to focus on a given area. Abbreviated
abbreviation for aperture value. Used on some camera information
displays as a shortened way to refer to aperture settings (f-stops)
light: the light that already
exists where a photograph is to be made, as opposed to light brought
in by the photographer. Often implies a relative dim light. Also
called ambient light or existing light