GLOSSARY^207
gamut The range of colors a device captures or creates. A color outside a device’s gamut is
represented by another color that is within the gamut of that device.
GIF (Graphics Interchange Format) A compressed image format. GIF was the first commonly
used image format on the Web, but it has been largely replaced by JPEG.
gigabyte (GB) A unit of data equal to 1,024 megabytes.
grayscale At least 256 shades of gray from pure white to pure black that represent the light and
dark portions of an image.
guide number A number keyed to the amount of light a flash emits. The number, divided by
the aperture setting, provides the distance to the subject for the optimum exposure. Divided by the
distance to the subject, the number yields the correct aperture setting.
histogram A graph showing the distribution of light and dark values throughout a photograph,
roughly equivalent to a photo’s dynamic range.
hot shoe A clip on the top of the camera to which you can attach a flash unit; it includes an elec-
trical link to synchronize the flash with the camera.
HSB The color model that most closely resembles the human perception of color. It is made up of
160,021,403,206 colors.
hue One of the three dimensions of color. (The others are saturations and brightness.) Hue is the
wavelength of light reflected from or transmitted through an object, seen in the visible spectrum. Red,
yellow, blue, and so on are the names of the hues. See also brightness and saturation.
I
IEEE 1394 A personal computer port capable of transferring large amounts of data at high
speeds, often used to upload graphic and video files. It’s known as i.Link on Sony systems and
FireWire on Apple computers.
image editor Software to edit and modify digital images. With an image editor, you can add
special effects and fix certain composition problems, as well as add new elements to the image.
image sensor A microchip that records images by converting the scene’s light values into an
analog electrical current that travels to a memory chip to be recorded as digital values.
intensity The amount of light reflected or transmitted by an object, with black as the lowest
intensity and white as the highest intensity.
intermittent flash Simulating a longer-lasting flash by repeatedly firing the flash unit(s) at high
speed. Intermittent flash is used for high-speed sync and modeling flash.
interpolation A process used in digital zooms and digital darkrooms to enlarge images by creat-
ing the new pixels. This is done by guessing which light values they should have based on the values
of the original pixels in the image that would be next to the new ones.See also zoom, digital
and zoom, optical.