VACUUM BACK

Definition: a camera back with a perforated plate through which air is drawn by a pump. A sheet of film is therefore sucked flat against the plate and held firmly during exposure. Used for special large format cameras such as copying devices where dimensional accuracy is critical.

VACUUM EASEL

Definition: a compact printing frame which ensures firm contact between the film and paper by excluding air between the surfaces. Some types are used to hold the paper flat on the enlarger baseboard when enlarging.

VALUE

Definition: The relative lightness or darkness of an area. Low values are dark high values are light.

Definition: A measure from white to black, the higher the value, the darker the image.

VANISHING POINT

Definition: the point at which parallel lines, viewed obliquely, appear to converge in the distance.

VAPOR DISCHARGE LAMP

Definition: a lamp in which electrical current passes through a vapor or gas rather than through a wire filament, thus producing illumination.

VAPOR LAMP

Definition: A lamp containing a gas or vapor that glows with light when an electric current passes through it. Mercury, neon and sodium vapor lamps produce strongly colored light. The light from fluorescent tubes is closer to daylight.

VARIABLE CONTRAST PAPER

Definition: a printing paper in which the contrast can be varied depending on the color of the printing light. This can be altered by using different color filters.

VARIABLE FOCUS LENS

Definition: a lens whose focal length can be continually varied within a given range. Also known as a zoom lens.

VARIABLE-CONTRAST PAPER

Definition: Photographic paper that provides different grades of contrast when exposed through special filters.

Definition: A printing paper in which varying grades of print contrast can be obtained by changing the color of the enlarging light source, as by the use of filters. Also called selectivecontrast paper. See also graded-contrast paper.

VECTIS

Definition: Minolta's brand name for their APS products.

VECTOR

Definition: An electronic or computer-readable image format incorporating a formulate representation of graphical line art. Vector format is used during the markup process, to keep redlines separate from images and to facilitate easy modifications. This format is also often used during the edit process.

VECTOR IMAGE

Definition: A computer image that uses mathematical descriptions of paths and fills to define the graphic, as opposed to individual pixels.

VEIL

Definition: a uniformly distributed silver deposit in a photographic image, not forming part of the image itself. Also known as fog.

VESA

Definition: Video Electronics Standards Association. A 32 bit display or other hardware card.

VIDEO NOISE

Definition: More commonly called "luminence signal-to-noise ratio. " This is a measure of how pure the video signal is (the monochrome or black-and-white portion of the picture). Tape with good luminence signal-to-noise ratios has a sharper, clearer image. This property has even greater importance on multiple generation copies.

VIDEO STILL CAMERA

Definition: a camera using an electronic charge coupled device instead of film.

VIEW CAMERA

Definition: A camera in which the taking lens forms an image directly on a ground-glass viewing screen. A film holder is inserted in front of the viewing screen before exposure. The front and back of the camera can be set at various angles to change focus and perspective. Used in architectural photography to eliminate perspective lines of tall buildings.

Definition: a large format camera which has a ground glass screen at the image plane for viewing and focusing.

Definition: A camera with movements in which the taking lens forms an image directly on a ground-glass viewing screen. A film holder is inserted in front of the ground glass for exposure. Also called large-format camera (typically producing images 4x5 inches or greater).

VIEWFINDER

Definition: (See Finder) Definition: a system used for composing and sometimes focusing the subject. There are several types: direct vision, optical, ground glass or reflex.

Definition: 1. A small window, screen or frame on a camera through which the photographer can see the area of a scene that will appear in the picture. 2. A camera that has a viewfinder, but not a rangefinder (which shows when the subject is focused).

Definition: Either an optical or electrical display used to frame in the camera.

VIEWING LENS

Definition: The lens on a camera through which the eye views the subject.

VIEWING SCREEN

Definition: The ground-glass element in a camera on which the subject is viewed.

Definition: In a reflex or view camera, the ground-glass surface on which the image is seen and focused.