Color Spaces

Colormath has a number of built-in color spaces and models.

A note on terminology

A color model defines the components of a color. For example, RGB is a color model that defines colors with the additive combination of red, green, and blue light.

A color space is a color model plus the details necessary to represent a color in that model. sRGB and DCI P3 are both color spaces the use the RGB model, but they define different values for the exact colors of their RGB primaries.

Built-in color models

RGB

• RGB

Component	Description	Range
r	red	[0, 1]
g	green	[0, 1]
b	blue	[0, 1]

The RGB color model defines colors with the additive combination of reg, green, and blue lights. RGB components are stored as floating point numbers in the range [0, 1]. You can also represent sRGB colors as packed integers with RGBInt, or create them from integers in the range [0, 255] with RGB.from255().

RGB color spaces

Colormath includes a number of built-in RGB color spaces, and you can define your own with RGBColorSpace. The default RGB space is sRGB.

• sRGB
• Linear sRGB
• ACES
• ACEScc
• ACEScct
• ACEScg
• Adobe RGB
• BT.2020 / REC.2020
• BT.709 / REC.709
• DCI P3
• Display P3
• ROMM RGB / ProPhoto RGB

HSL

• HSL

Component	Description	Range
h	hue, degrees, NaN for monochrome colors	[0, 360)
s	saturation	[0, 1]
l	lightness	[0, 1]

A cylindrical representation of sRGB using Hue, Saturation, and Lightness.

HSV

• HSV

Component	Description	Range
h	hue, degrees, NaN for monochrome colors	[0, 360)
s	saturation	[0, 1]
v	value	[0, 1]

A cylindrical representation of sRGB using Hue, Saturation, and Value / brightness.

HWB

• HWB

Component	Description	Range
h	hue, degrees	[0, 360)
w	whiteness	[0, 1]
b	blackness	[0, 1]

A cylindrical representation of sRGB using Hue, Whiteness, and Blackness.

HSLuv and HPLuv

• HSLuv

Component	Description	Range
h	hue, degrees, NaN for monochrome colors	[0, 360)
s	saturation	[0, 100]
l	lightness	[0, 100]

• HPLuv

Component	Description	Range
h	hue, degrees, NaN for monochrome colors	[0, 360)
p	percentage saturation	[0, 100]
l	lightness	[0, 100]

HSLuv and HPLuv are color spaces designed as a human friendly alternative to HSL.

IC_tC_p

• ICtCp

Component	Description	Range
I	intensity	[0, 1]
Ct	Tritan (blue-yellow)	[-0.5, 0.5]
Cp	Protan (red-green)	[-0.5, 0.5]

IC_tC_p is a color space designed for high dynamic range and wide color gamut imagery.

J_zA_zB_z and J_zC_zH_z

• JzAzBz

Component	Description	Range
Jz	lightness	[0, 1]
Az	green-red	[-1, 1]
Bz	blue-yellow	[-1, 1]

• JzCzHz

Component	Description	Range
Jz	lightness	[0, 1]
Cz	chroma	[-1, 1]
Hz	hue, degrees, NaN for monochrome colors	[0, 360)

J_zA_zB_z is a perceptually uniform space where euclidean distance predicts perceptual difference. J_zC_zH_z is its cylindrical representation.

CIE L*a*b* and LCH_ab

• LAB

Component	Description	Range
L	lightness	[0, 100]
a*	green-red	[-128, 128]
b*	blue-yellow	[-128, 128]

• LCHab

Component	Description	Range
L	lightness	[0, 100]
c	chroma	[0, 150]
h	hue, degrees, NaN for monochrome colors	[0, 360)

LAB is a color model intended to be perceptually uniform. Its cylindrical representation is LCH_ab.

LAB and LCHab color spaces

• LABColorSpaces
• LCHabColorSpaces

LAB and LCHab models each have multiple color spaces that are defined relative to a white point. The default white point is D65.

CIE L*u*v* and LCH_uv

• LUV

Component	Description	Range
L	lightness	[0, 100]
u		[-100, 100]
v		[-100, 100]

• LCHuv

Component	Description	Range
L	lightness	[0, 100]
c	chroma	[0, 100]
h	hue, degrees, NaN for monochrome colors	[0, 360)

LUV is a color model intended to be perceptually uniform. Its cylindrical representation is LCH_uv.

LUV and LCHuv color spaces

• LUVColorSpaces
• LCHuvColorSpaces

LUV and LCHuv models each have multiple color spaces that are defined relative to a white point. The default white point is D65.

Oklab and Oklch

• Oklab

Component	Description	Range
L	lightness	[0, 1]
a	green-red	[-0.4, 0.4]
b	blue-yellow	[-0.4, 0.4]

• Oklch

Component	Description	Range
L	lightness	[0, 1]
c	chroma	[0, 0.4]
h	hue, degrees, NaN for monochrome colors	[0, 360)

Oklab is a perceptual color space for image processing. Its cylindrical representation is Oklch.

CIE XYZ

• XYZ

Component	Range
X	[0, 1]
Y	[0, 1]
Z	[0, 1]

The XYZ color model is common used as a profile connection space when converting between other models.

XYZ color spaces

• XYZColorSpaces

The XYZ model has multiple color spaces that are defined relative to a white point. The default white point is D65.

ANSI color codes

• ANSI16
• ANSI256

Based on the VGA color palette, there are models for 4-bit, 16 color codes and 8-bit, 256 color codes

CMYK

• CMYK

Component	Description	Range
c	cyan	[0, 1]
m	magenta	[0, 1]
y	yellow	[0, 1]
k	key / black	[0, 1]

Colormath’s CMYK model uses device-independent conversions. Device CMYK profiles are not currently supported.