D-MIN

Definition: Minimum density. The smallest density in a image. Also, the smallest density possible for a particular film or paper.

D-RAM (DYNAMIC RANDOM ACCESS MEMORY)

Definition: The term describes memory within the computer that is constantly changing.

D/LOG E CURVE

Definition: A graph of density (D) against the logarithm of exposure (log E) Used in sensitometry to compare the sensitivity of different emulsions to light.

D50

Definition: The CIE Standard Illuminant that represents a colour temperature of 5000 K. This is the colour temperature that is most widely used in graphic arts industry viewing booths.

D65

Definition: The CIE Standard Illuminant that represents a colour temperature of 6504 K.

DAGUERREOTYPE

Definition: 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 plate coated with silver iodide.

Definition: first practical and commercial photographic process, introduced by Louis Daguerre in 1839. The sensitive material comprised silver iodide, deposited on a polished silver plated copper base. A positive image was produced by camera exposure and mercury "development", which turned light struck halides gray-white. The image was made permanent by immersing the plate in a solution of sodium chloride.

DARK SLIDE

Definition: See slide (2).

DARKCLOTH

Definition: Material used to cover the photographer's head and camera to block surrounding light in order to better view the image on the camera's ground glass viewing screen.

Definition: cloth made of dark material placed over the photographers head and the camera back to facilitate the viewing of images on the ground glass screen of sheet film cameras.

DARKFIELD

Definition: method of illumination used in photomicography that will show a specimen against a dark or black background.

DARKROOM

Definition: A room where photographs are developed and printed sufficiently dark to handle light-sensitive materials without causing unwanted exposure.

Definition: light tight room used for processing and printing. It usually incorporates safe lighting suitable for the materials in use.

Definition: A lighttight area used for processing films and for printing and processing papers; also for loading and unloading film holders and some cameras.

Definition: A room or small area that can be made completely lightproof, so it can be used for working with photographic film, paper, or other light-sensitive materials.

DARKSLIDE

Definition: slide-in plastic sheet used on sheet film cameras over the front of the film holder to protect the emulsion from light.

DAT (DIGITAL AUDIO TAPE)

Definition: A recording format that is commonly used for data storage and data backup because of its low cost per megabyte.

DATA

Definition: The number that make up a digital file.

DATA COMPRESSION

Definition: Digital cameras don't have the massive amounts of storage a computer does, yet they create files that can be quite large. Because of this, the camera compresses used, the better the image. The more compression used, the more images can be stored.

Definition: The process of reducing the size of a data file, usually accomplished through software processing.

DATA DISK

Definition: A circular, rotating disk at the end of Advanced Photo System film cassettes that functions as a circular bar code, communicating the film speed, type and exposure length through a sequence of reflective bars to an optical sensor in the camera.

DATABASE

Definition: A database is a collection of data that is organized so that its contents can easily be accessed, managed, and updated.

DAYLIGHT BALANCE

Definition: Most film available on the market today is Daylight Balanced. Unless the film specifically states that it is balanced for other lighting conditions, it will probably be designed for daylight. This film will produce natural colors when exposed under natural (outdoors) conditions or under normal flash. When shot under tungsten lighting (incandescent light bulbs) there will be a reddish yellow tint to the photo and when shot under fluorescent lighting there will be a green hue.

DAYLIGHT COLOR FILM

Definition: color film intended for use with daylight or a light source of similar temperature. The film is color balanced to 5400 K.

DAYLIGHT ENLARGER

Definition: early type of enlarger using light from a hole in a window to provide illumination of the negative.

DAYLIGHT FILM

Definition: 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 a blue flashbulb.

Definition: Film balance to give correct rendition when shooting under average daylight and flash illumination, approximately 5500K.