# Luminance Outputs a grayscale value containing the luminance of the incoming RGB color in all color channels. ## Parameter Types **Luminance (color3f):** |Input |Type | |-------------------|-------------| |`In` |Color3| |`Luma Coefficients`|Color3| |Output|Type | |------|-------------| |`Out` |Color3| **Luminance (color4f):** |Input |Type | |-------------------|-------------| |`In` |Color4| |`Luma Coefficients`|Color3| |Output|Type | |------|-------------| |`Out` |Color4| ## Parameter descriptions - `In`: The input to convert to grayscale. - `Luma Coefficients`: The luma coefficients of the color space. The possible values for this node are the luma coeffiecients for the color spaces `acescg`, `rec202/rec2100`, or `rec709`. The default value is the luma coeffiecients for `acescg`, which are `(0.2722287, 0.6740818, 0.0536895)`. ## Discussion The Luminance node takes in a color input and outputs that input as a grayscale image. The node computes the grayscale of an image by taking the dot product of the luma coefficients and the color vector. Below is an example of a simple node graph that uses the luminance node to convert an image to grayscale:  Below, the resulting texture applies 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)