Next: , Previous: Color Difference Metrics, Up: Color


5.11.5 Color Conversions

This package contains the low-level color conversion and color metric routines operating on lists of 3 numbers. There is no type or range checking.

(require 'color-space)

— Constant: CIEXYZ:D65

Is the color of 6500.K (blackbody) illumination. D65 is close to the average color of daylight.

— Constant: CIEXYZ:D50

Is the color of 5000.K (blackbody) illumination. D50 is the color of indoor lighting by incandescent bulbs.

— Constant: CIEXYZ:A
— Constant: CIEXYZ:B
— Constant: CIEXYZ:C
— Constant: CIEXYZ:E

CIE 1931 illuminants normalized to 1 = y.

— Function: color:linear-transform matrix row
— Function: CIEXYZ->RGB709 xyz
— Function: RGB709->CIEXYZ srgb
— Function: CIEXYZ->L*u*v* xyz white-point
— Function: CIEXYZ->L*u*v* xyz
— Function: L*u*v*->CIEXYZ L*u*v* white-point
— Function: L*u*v*->CIEXYZ L*u*v*

The white-point defaults to CIEXYZ:D65.

— Function: CIEXYZ->L*a*b* xyz white-point
— Function: CIEXYZ->L*a*b* xyz
— Function: L*a*b*->CIEXYZ L*a*b* white-point
— Function: L*a*b*->CIEXYZ L*a*b*

The XYZ white-point defaults to CIEXYZ:D65.

— Function: L*a*b*->L*C*h L*a*b*
— Function: L*C*h->L*a*b* L*C*h
— Function: CIEXYZ->sRGB xyz
— Function: sRGB->CIEXYZ srgb
— Function: CIEXYZ->xRGB xyz
— Function: xRGB->CIEXYZ srgb
— Function: sRGB->xRGB xyz
— Function: xRGB->sRGB srgb
— Function: CIEXYZ->e-sRGB n xyz
— Function: e-sRGB->CIEXYZ n srgb
— Function: sRGB->e-sRGB n srgb
— Function: e-sRGB->sRGB n srgb

The integer n must be 10, 12, or 16. Because sRGB and e-sRGB use the same RGB709 chromaticities, conversion between them is simpler than conversion through CIEXYZ.

Do not convert e-sRGB precision through e-sRGB->sRGB then sRGB->e-sRGB – values would be truncated to 8-bits!

— Function: e-sRGB->e-sRGB n1 srgb n2

The integers n1 and n2 must be 10, 12, or 16. e-sRGB->e-sRGB converts srgb to e-sRGB of precision n2.