Color depth (or bit depth) is the number of bits per channel (bpc) used to represent the color of a pixel. The more bits for each RGB channel (red, green, and blue), the more colors can be represented.

In After Effects, you can work in 8-bpc, 16-bpc, or 32-bpc color.

In addition to bit depth, a separate characteristic of the numbers used to represent pixel values is whether the numbers are integers or floating-point numbers. Floating-point numbers can represent a larger range of numbers with the same number of bits. In After Effects, 32-bpc pixel values are floating-point values.

8-bpc pixels can have values for each color channel from 0 (black) to 255 (pure color). 16-bpc pixels can have values for each color channel from 0 (black) to 32,768 (pure color). If all three color channels have the maximum, pure-color value, the result is white. 32-bpc pixels can have values under 0.0 and values over 1.0 (pure color); this means that 32-bpc color in After Effects is also high dynamic range (HDR) color. HDR values can be much brighter than white. (See High dynamic range color.)

Glow effect and Gaussian Blur effect applied to image in 32-bpc project (left) and 16-bpc project (right)

Set the project color depth to 32 bpc to work with HDR footage or to work with over-range values—values above 1.0 (white) that aren’t supported in 8- or 16-bpc mode. Over-range values preserve the intensity of highlights, which is just as useful for synthetic effects such as lights, blurs, and glows as it is for working with HDR footage. The headroom provided by working in 32 bpc prevents many kinds of data loss during operations from color correction to color profile conversion. Even if you’re using 8-bpc footage and are creating movies in 8-bpc formats, you can obtain better results by having the project color depth set to 16 or 32 bpc. Working in a higher bit depth provides higher precision for calculations and greatly reduces quantization artifacts, such as banding in gradients.

Because 16-bpc frames use half the memory of 32-bpc frames, rendering previews in a 16-bpc project is faster, and RAM previews can be longer than in a 32-bpc project. 8-bpc frames use even less memory, but the tradeoff between quality and performance can be quite visible in some images at a project color depth of 8 bpc.

Project Settings button in the Project panel

You can specify a color depth for each render item, which overrides the project color depth when rendering for final output. You can also specify the color depth to use for each output item in the output module settings.

Though many effects can work with all color depths, some effects work only with lower color depths. You can set the Effects & Presets panel to only show effects that work with your current project color depth. (See Effects & Presets panel overview.)