camera or projector to secure the sharpest possible
image of the object.
FOGNonimage photographic density. The defect is
due either to the action of a stray light, to improperly
compounded processing solutions, or to wrongly
stored or outdated photographic materials.
FOREGROUND (PHOTOGRAPHY)That part of
the landscape imaged in a horizontal or oblique
photograph that is closer than the principal object to
the camera. (ASP)
GUIDE NUMBERValues assigned to photographic
flood and flash lamps according to American
Standard to rate their light output in terms useful in
exposure calculation. The guide number for a
particular lamp used with a particular film is divided
by the distance in feet from the lamp to the subject
to find the f/number.
HALATION A halo or ghost image surrounding the
true image of a bright object on a photographic
emulsion, caused by reflection of rays of light from
the back of the negative material.
FRAME(l) Any single exposure contained within a
continuous sequence of photographs. (2) The
smallest unit in television or film-a single picture.
A complete scanning cycle of the two fields every
l/30 second. A frame equal to 525 scanning lines.
FREEZE FRAMEArrested motion that is perceived
as a still shot.
FULL APERTUREThe maximum opening of a lens
FULL STOPThe standard series of diaphragm
markings, or stop openings, that are 0.7, 1.0, 1.4,
2.0, 2.8, 4.0, 5.6, 8, 11, 16, 22, 32, 45, 64, 90, and
FUZZINESS Lack of image sharpness caused by a
defective lens, poor focus, movement, and so forth.
GAINThe level of amplification for video or audio
signals. Increasing the video gain increases the
GENERATIONThe number of dubs or copies sway
from the original recording. The greater number of
generations, the greater loss of picture quality.
GRADUATEA container for liquids marked off to
measure various volumes. (PIA)
GRAINThe discrete particles of image silver in
photographs. The random distribution of these
particles in an area of uniform exposure gives rise
to the appearance known as graininess."
GRAININESSThe subjective impression of non-
uniformity in an area of a photograph corresponding
to uniform exposure, most often noticeable in
enlargements with a magnification of 10 or more.
GRANULARITYAn objective quantitative measure
GROUND GLASSA sheet of glass with a grained or
matte (translucent) surface, a focusing screen,
diffusing screen, and so forth. (PIA)
HALFTONEReproduction of a photograph in which
the gradation of tone is reproduced by various sized
dots and intermittent white spaces caused by
interposing a screen between the lens and the film.
HALIDEAny compound of chlorine, iodine, bromine,
or fluorine, and silver. Silver bromide, silver
chloride, and silver iodide are the light-sensitive
materials in silver emulsions.
HANGER, FILMA frame, usually of metal or plastic,
for holding one or more photographic films to
facilitate handling during processing.
HARDENERA chemical that increases the melting
point of gelatin in photographic layers and prevents
softening in warm-processing baths. Hardeners
commonly used in photographic processing baths
are aluminum potassium sulfate, chromium
potassium sulfate, and formaldehyde solution.
HAZEThe presence of foreign matter in the
atmosphere to an extent sufficient to reduce even
slightly its transparency.
HEAD-ON SHOTA directionless shot in which the
subject comes directly toward the camera. Used to
change screen direction.
HEADSA small assembly within an audio or video
recording system that can erase, record, or playback
the signal in electromagnetic impulses.
HELICAL SCAN, OR HELICAL VTR (ALSO
CALLED SLANT TRACK)A videotape
recording or a videotape recorder in which the video
signal is put on tape in a slanted, diagonal way.
Because the tape wraps around the head drum in a
spiral-like configuration, it is called helical.
HIGH-ANGLE SHOTA scene photographed on a
downward angle; the camera being placed above the