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CIE - Commission Internationale De l'Eclairage

SmartNote: 22
Type: WebSite
ColorGeek factor:

Link: http://www.cie.co.at/cie/
(will open in a new browser window)

See Also

Term: CIELab, Lab
Term: CIExyY, xyY

Gamma

SmartNote: 221
Type: Term
ColorGeek factor: unrated
A non-standardized measure of contrast for color scanners, video monitors and photographic materials. A gamma of 1.0 usually means normal or no change in contrast, except in Macintosh monitors where gamma 1.8 is standard. Higher gamma numbers usually mean more contrast with darker mid-tones. Lower gamma numbers usually mean lower contrast and lighter mid-tones. Gamma pivots on (does not change) the white and black point of an image. Gamma is typically applied by raising fractional L*, fractional RGB or fractional XYZ to the power of gamma.

See Also

Term: Curves, tone curves

Gamut Compression

SmartNote: 223
Type: Term
ColorGeek factor: unrated
A form of gamut mapping in which the range of color values produced by an input device (e.g. a color scanner) is reduced to fit within the smaller available gamut of the output device (e.g. a CMYK press). Gamut compression can be crucial to good color reproduction but colors that have been gamut compressed will seldom match the original.

Gamut Mapping

SmartNote: 224
Type: Term
ColorGeek factor: unrated
The redistribution of color values from an input device (e.g. color scanner or printer) to fit the smaller or larger gamut of the output device. If the input gamut is larger than the output gamut, gamut mapping is the same as Gamut Compression. If the input gamut is smaller than the output gamut, colors and contrast can be intensified through Gamut Expansion, or colors can be mapped to their exact equivalents, e.g. for digital proofing.

GCR Gray Component Replacement

SmartNote: 225
Type: Term
ColorGeek factor: unrated
The replacement of some or all of the CMY inks in a CMYK pixel with enough black ink to restore the pixel to the same visual appearance. (see UCA, UCR).

See Also

Term: Process color
Term: Color Separations
Term: Profiling

Gradation Control

SmartNote: 226
Type: Term
ColorGeek factor: unrated
A means of adjusting tonal contrast of specific tonal regions, either equally for all colorants or imaging channels, or separately for independent channels.

Gradation

SmartNote: 227
Type: Term
ColorGeek factor: unrated
The relationship of reproduced lightness values to original lightness values in an imaging process, usually expressed as a "tone curve".

Hi-Fi Color

SmartNote: 228
Type: Term
ColorGeek factor: unrated
Any process that increases the color gamut of an output imaging device (printer). Usually refers to adding extra inks and plates to the traditional CMYK set to improve the color gamut of offset lithography. The three main Hi-Fi methods are; the Küppers approach (CMYK+RGB), Pantone(r) Hexachrome? (CMYK + Orange & Green) and MaxCMY (CMYK + extra CMY).

See Also

Term: Pantone Colors
Term: N-color