The CIELAB color space, also referred to as L*a*b* , is a color space defined by the International Commission on Illumination (abbreviated CIE) in 1976. (Referring to CIELAB as "Lab" without asterisks should be avoided to prevent confusion with Hunter Lab.) It expresses color as three values: L* for perceptual lightness, and a* and b* for the four unique colors of human vision: red, green, blue, and yellow. CIELAB was intended as a perceptually uniform space, where a given numerical change corresponds to a similar perceived change in color. While the LAB space is not truly perceptually uniform, it nevertheless is useful in industry for detecting small differences in color. Like the CIEXYZ space it derives from, CIELAB colorspace is a device-independent, "standard observer" model. The colors it defines are not relative to any particular device such as a computer monitor or a printer, but instead relate to the CIE standard observer which is an averaging of the results of color matching e
The CIELAB color space, also referred to as L*a*b* , is a color space defined by the International Commission on Illumination (abbreviated CIE) in 1976. (Referring to CIELAB as "Lab" without asterisks should be avoided to prevent confusion with Hunter Lab.) It expresses color as three values: L* for perceptual lightness, and a* and b* for the four unique colors of human vision: red, green, blue, and yellow. CIELAB was intended as a perceptually uniform space, where a given numerical change corresponds to a similar perceived change in color. While the LAB space is not truly perceptually uniform, it nevertheless is useful in industry for detecting small differences in color.
Like the CIEXYZ space it derives from, CIELAB colorspace is a device-independent, "standard observer" model. The colors it defines are not relative to any particular device such as a computer monitor or a printer, but instead relate to the CIE standard observer which is an averaging of the results of color matching experiments under laboratory conditions. en.wikipedia.org
А теперь по-русски:
Lab - обладает самым широким цветовым диапазоном (охватом) за счет того, что в нем используется не три и даже четыре базовых цвета. В модели есть три канала:
- «L» — это светлота. Она устанавливает координаты света (100) и границы теней (0).
- a — спектр от зеленого через серый к пурпурному
- b — спектр от синего через серый к желтому.
Параметры a и b могут принимать по 256 значений от -127 до 127. Но при этом их отрицательные значения соответствуют холодным тонам, а положительные – теплым. Как правило, в нулевые значения каналов a и b дают ахроматическую гамму.