Diffuse Color Channel

This page describes the Diffuse Channel and how it is used to have more control of a final composited image.

Overview

The Diffuse channel shows the colors and textures used in materials, flatly applied to objects with no lighting information. The colors are the actual colors set in the material definition, and each texture appears as it does in the texture (file) itself. There are no highlights or shadows, and any background image is not included.

Other render elements that include colors from materials are said to include the diffuse contribution or the diffuse component of the rendered scene. The Diffuse channel contributes this diffuse component; any render element that includes this diffuse component is a combination of Diffuse and other render channel(s).

This render element is, by itself, useful for making overall adjustments and enhancements to base colors and textures during compositing without affecting things like reflections and highlights.

UI Path

||Node Editor|| > Add > Render Channels > Color Channel > Type > Diffuse

Common Uses

The Diffuse channel is useful for changing the appearance of many passes when it is combined with Raw render passes (like Raw GI, Raw Light, etc.). In the example below, the Diffuse is multiplied by the Raw GI to provide the Global Illumination pass. In this way, color correction can be performed upon the raw pass without the actual diffuse colors being changed, making it possible to tint a pass in a realistic way without re-rendering.

The Diffuse channel is a very useful due to the number of raw passes with which it can be combined, giving the ability to manipulate many areas of the render at the composite level. The Diffuse pass can also be color-corrected on its own, as shown in the example below. In this case, a Multi Matte render element was used in conjunction with the Diffuse to isolate the center of the upper ring and change its color from yellow to green without also tinting its lighting or shadowing in any way.