Helmgenlch

The Helmgenlch color space is not registered in Color by default

Properties

Name: helmgenlch

White Point: D65 / 2˚ (Variant from ASTM-E308)

Coordinates:

Name	Range^*
`l`	[0, 1.0]
`c`	[0, 0.65]
`h`	[0, 360]

^* Space is not bound to the range and is only used as a reference to define percentage inputs/outputs.

Helmlab is a family of purpose-built color spaces, two to be exact. The first is the Helmlab Metric space which is designed for perceptual distance measurements, claiming STRESS 23.30 on COMBVD - 20% better than CIEDE2000. The second is the Helmgen space which is designed for gradient and palette generation (60-8 vs Oklab on ColorBench's 83 metrics, 360/360/360 gamut cusps, zero monotonicity violations).

Helmgenlch is the polar form of Helmgen and is the generation-optimized space and is specifically used for interpolation, palettes, etc. It is the general purpose color space of the Helmlab family.

Learn more.

Channel Aliases

Channels	Aliases
`l`	`lightness`
`c`	`chroma`
`hue`	`hue`

Inputs

The Helmlab space is not currently supported in the CSS spec, the parsed input and string output formats use the color() function format using the custom name --helmgenlch:

color(--helmgenlch l a b / a)  // Color function

The string representation of the color object and the default string output use the color(--helmgenlch l a b / a) form.

>>> Color("helmgenlch", [0.56321, 0.34823, 32.189])
color(--helmgenlch 0.56321 0.34823 32.189deg / 1)
>>> Color("helmgenlch", [0.75752, 0.26718, 72.88]).to_string()
'color(--helmgenlch 0.75752 0.26718 72.88)'

Registering

from coloraide import Color as Base
from coloraide.spaces.helmgenlch import Helmgenlch

class Color(Base): ...

Color.register(Helmgenlch())