Version: Unity 6 (6000.0)
Language : English
Color spaces in Unity
Gamma color space

Differences between linear and gamma color space

When using linear rendering, input values to the lighting equations are different to those in gamma space. This means differing results depending on the color space. For example, light striking surfaces has differing response curves, and Image Effects behave differently.

Light fall-off

The fall-off from distance and normal-based lighting differs in two ways:

  • When rendering in linear mode, the additional gamma correction that is performed makes a light’s radius appear larger.

  • Lighting edges also appear more clearly. This more correctly models lighting intensity fall-off on surfaces.

Left: Lighting a sphere in linear space. Right: Lighting a sphere in gamma space
Left: Lighting a sphere in linear space. Right: Lighting a sphere in gamma space

Linear intensity response

When you are using gamma rendering, the colors and Textures that are supplied to a ShaderA program that runs on the GPU. More info
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already have gamma correction applied to them. When they are used in a Shader, the colors of high luminance are actually brighter than they should be compared to linear lighting. This means that as light intensity increases, the surface gets brighter in a nonlinear way. This leads to lighting that can be too bright in many places. It can also give models and scenesA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
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a washed-out feel. When you are using linear rendering, the response from the surface remains linear as the light intensity increases. This leads to much more realistic surface shading and a much nicer color response from the surface.

The Infinite 3D Head Scan image below demonstrates different light intensities on a human head model under linear lighting and gamma lighting.

Infinite 3D Head Scan by Lee Perry-Smith, licensed under a Creative Commons Attribution 3.0 Unported License (available from www.ir-ltd.net)
Infinite 3D Head Scan by Lee Perry-Smith, licensed under a Creative Commons Attribution 3.0 Unported License (available from www.ir-ltd.net)

Linear and gamma blending

When blending into a framebuffer, the blending occurs in the color space of the framebuffer.

When you use gamma space rendering, nonlinear colors get blended together. This is not the mathematically correct way to blend colors, and can give unexpected results, but it is the only way to do a blend on some graphics hardware.

When you use linear space rendering, blending occurs in linear color space: This is mathematically correct and gives precise results.

The image below demonstrates the different types of blending:

Top: Blending in linear color space produces expected blending results<br/>Bottom: Blending in gamma color space results in over-saturated and overly-bright blends
Top: Blending in linear color space produces expected blending results
Bottom: Blending in gamma color space results in over-saturated and overly-bright blends
Color spaces in Unity
Gamma color space