# Matte A merge operation that layers premultiplied foreground over background. ## Parameter Types |Input |Type | |------------|-------------| |`Foreground`|Color4| |`Background`|Color4| |`Mix` |Float | |Output|Type | |------|-------------| |`Out` |Color4| ## Parameter descriptions - `Foreground`: The `color4` foreground input. `F` represents the RGB component of this parameter. `f` represents the alpha component of this parameter. - `Background`: The `color4` background input. `B` represents the RGB component of this parameter. `b`represents the alpha component of this parameter. - `Mix`: The weight of the blend operation. The higher the value of `Mix`, the more apparent the effect of the blend operation. The default value is `1`. Values outside of the range `0-1` produce an undefined effect outside of the node’s intended function. ## Discussion The Matte node determines its output using the alpha channels of the foreground and background inputs. The RGB component of the output is `Ff+B(1-f)` and the alpha component of the output is `f+b(1-f)`. Below is a simple node graph that uses the In node to blend a wood and rock texture.  Below are the two original images, the image representation of the alpha of the foreground, and the resulting blended texture applied to a cube.     --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)