D
demosaic An algorithm used to fill in missing color information from an image captured by a
camera’s mosaic sensor.density The capability of a color to stop or absorb light; the more light absorbed or the less light
reflected, the higher the density.depth of field The area between the nearest and farthest points that are in focus through a cam-
era lens. Depth of field increases at smaller lens apertures.Design Rule for Camera File System (DCF) An industry standard for saving digital images.
This not only determines the file type, but also sets the rule for naming the folder and file structure.
It allows the conversion of uncompressed TIFF files into compressed JPEG files.diaphragm (Alsoiris.) A mechanism located in a lens that controls how much light passes
through the lens. It is typically made of overlapping, interlocked leavesthat form a roughly circular
opening in the center of the diaphragm. When the exposure ring on the lens is twisted, the leaves
contract or expand to allow more or less light through. See also shutter.diffuser A translucent plastic or cloth placed between a flash and the subject. The diffused light
softens shadows and contrast.digital The measurement and recording of continuously varying values such as sound and light by
frequently sampling the values and representing them with discrete numerical values, usually
expressed as binary numbers. See also analog.dithering The process of creating different colors by placing dots of ink coloring near each other
in different combinations to create the illusion of other colors.dots per inch (dpi) A measurement of resolution used for scanning and printing.
dye-sublimation printer The printing system that transfers colors from ribbons containing dyes
that are heated and fused onto paper. Dye-sublimation printers are continuous-tone printers capable
of producing photographic quality images.dynamic range The range of the lightest to the darkest areas in an image. Its value is expressed
as the ratio of contrast, tonal range, or density in an image between black and white. The number
0.0 represents white, and 4.0 is black. A flatbed scanner may have a dynamic range of 2.4–2.7
whereas a drum scanner may be as high as 3.6–3.8. The numeric ranges express the capability of
the devices to record and reproduce the range of grays between black and white. The higher the
number, the greater the detail in shadows and highlights in an image. Film is generally given a
dynamic range of 4.0; most digital cameras and scanners range from 2.4–3.0. Dynamic range may
also refer to the ratio of the maximum signal level a system can produce compared to its noise, or
static, level. Also known as signal-to-noiseratio.See also histogram.(^204204) GLOSSARY