Graphics Programs Reference
In-Depth Information
ICM
: The Windows Color Management System. ICM uses the Heidelberg
CMM, the color matching method used by Windows Me, 98, 95, XP, and
2000.
Illuminant:
A mathematical description of a real or imaginary light source
described by its spectral power distribution. Illuminants normally are
specified in terms of the relative energy for each wavelength. Over the
years, the CIE produced specific classes of illuminants, such as D50, D65,
known as CIE Standard Illuminants. Illuminant A was designated to
represent tungsten light and Illuminant D was designated to represent
daylight. Some illuminants are tied to the relative energy distributions
that correspond to the radiation emitted by a so-called blackbody (see
also
Color Temperature
). D illuminants are based on the daylight curve that
runs above the blackbody. Therefore, D50 has a spectral energy distribu-
tion that closely matches that of a blackbody at 5000 K, and D65 would
closely match that of a blackbody at 6500 K.
Input profile:
An ICC profile that reflects the behavior of an input device
like a scanner or digital camera. Some use the term to describe the source
profile used when producing color space conversions, which require two
sets of profiles (source and destination). However, ideally, input profile
should be used to describe a profile that characterizes an input (capture)
device.
Kelvin:
A unit of absolute temperature. An object at zero Kelvin has no
energy. This is often referred to as absolute zero (the coldest any object
can be). See also
Color temperature
.
LAB:
A color model created by the CIE, LAB is a device-independent color
space with a number of refinements. Also known officially as CIELAB,
LAB is a synthetic color space based on no single or real-world device.
LAB is a perceptually uniform space that works well for mathematical
transforms. CIELAB is a refinement of the CIE XYZ (1931) color model
that is based upon how humans actually see color. See also
CIE L*a*b*
.
LCH:
Luminance/chroma/hue; a three-dimensional color model that
describes a color by separating luminance (lightness) from chroma
(saturation) and hue (color). LCH is a device-independent color space.
Lightness:
The lightness (or brightness) of a color, independent of its hue
and saturation.
Liquid crystal display (LCD):
A display technology using a special polymer
coating, which holds liquid crystals between two sheets of polarized
transparent material. When an electric current is passed through indi-
vidual crystals, they alter their orientation and change the polarization,
thus allowing a backlight to come through, producing an image.
Luminance:
A measure of the visible electromagnetic radiation; lumi-
nance unit equal to 1 candle per square meter measured perpendicular
