Color

Hair shading simulates color through melanin properties and explicit color control:

• Melanin concentration and type (eumelanin/pheomelanin ratio) model biological hair pigments

• Base color overrides provide direct RGB control for non-natural hair colors

• Both methods affect surface color and internal light scattering

Parameters

Display Name	Name	Type	Default
Base	base_color_weight	float	1.0
Color	base_color	color	1.0, 1.0, 1.0
Melanin Presets	melanin_concentration_preset	enum	melanin_concentration_custom
Melanin	melanin_concentration	float	1.0
Melanin Redness	melanin_redness	float	0.5
Melanin Randomize	melanin_concentration_randomize	float	0.0

The hair fiber absorption can be controlled by setting the color parameter or adjusting the melanin concentration parameter.

Note

In the path-tracer mode, overlapping hair fibers with low melanin concentration or light-color dye may appear dark. To reduce the darkening, one may need to increase the Max Bounces setting.

Please see RTX Interactive (Path Tracing) mode render settings for more information.

Max Bounces: 4

Flamingo Hair Dye

Max Bounces: 256

Flamingo Hair Dye

Note

In the RTX – Interactive (Path Tracing) mode, to reduce the noise within hair fibers with low melanin concentration or light dye color, one may need to increase the Total Samples per Pixel setting.

Please see RTX Interactive (Path Tracing) mode render settings for more information.

Total Samples per Pixel: 8

Icy Light Blue Hair Dye

Total Samples per Pixel: 32

Icy Light Blue Hair Dye

Total Samples per Pixel: 64

Icy Light Blue Hair Dye

Total Samples per Pixel: 256

Icy Light Blue Hair Dye

Base

This parameter sets the brightness of the hair fiber color.

Base: 0.1

Green Ombre Dye

Base: 0.25

Green Ombre Dye

Base: 0.5

Green Ombre Dye

Base: 1.0

Green Ombre Dye

Color

This parameter sets the hair fiber color by adjusting the absorption within the hair fiber volume. The color parameter can create a dyed or art-directed hair look.

Pretty Purple

Rainbow

Note

For dyed hair, one should set the melanin concentration parameter to 0.0; otherwise, melanin and pheomelanin will darken the dye color.

Tip

For realistic hair color, set this parameter to white, and adjust the melanin concentration parameter instead.

Melanin Presets

This parameter presents a list of known melanin concentration values for different hair types. One can use a custom melanin concentration by setting this parameter to melanin_concentration_custom and enter a value for the melanin concentration parameter.

Melanin concentration “presets” are including:

Fiber Color	Melanin Concentration
White	0.0
Platinum Blond	0.0025
Light Blonde	0.10
Dark Blonde	0.30
Dark Brown	0.65
Black	1.0

Melanin

This parameter sets the melanin concentration, which controls the hair fiber’s primary color. At 0.0, hair fiber appears completely translucent, while at 1.0, pigments blocking refracted rays. Thus the hair fiber becomes black.

Melanin Concentration: 0.025

Platinum Blonde / Silver

Melanin Concentration: 0.05

Shimmering Sands Light Blonde

Melanin Concentration: 0.1

Sun-Kissed Light Blonde

Melanin Concentration: 0.2

Blonde

Melanin Concentration: 0.35

Light Brown

Melanin Concentration: 0.5

Brown

Melanin Concentration: 0.75

Dark Brown

Melanin Concentration: 1.0

The Crow - Black

Melanin Redness (Pheomelanin)

This parameter sets the melanin redness, which is the ratio between brown eumelanin and red pheomelanin. At higher values, the hair fiber becomes redder. The melanin redness has no effects when the melanin concentration parameter is 0.0.

Melanin Redness (Pheomelanin): 0.0

Melanin Redness (Pheomelanin): 0.5

Melanin Redness (Pheomelanin): 0.75

Melanin Redness (Pheomelanin): 1.0

Melanin Randomize

This parameter randomizes the amount of melanin concentration within hair fibers.

Note

The melanin randomization is not supported yet, one may map a texture noise to the melanin concentration parameter instead.

Melanin Randomization: 0.0

Melanin Randomization: 1.0