Main toolbar > Curve Editor (Open) > Select a material color track in the Track View hierarchy. > Track View menu bar > Controller
menu > Assign > Color RGB
Graph Editors > Track View – Curve Editor > Select a material color track in the Track View hierarchy. > Track View menu bar
> Controller menu > Assign > Color RGB

The Color RGB controller splits the R, G, and B components into three separate tracks. You can use this controller with color tracks. By default, each track is assigned a Bezier Float controller. The Bezier Float controller is a single parameter controller.
Note: The Color RGB and the Point3 XYZ controllers are identical in function, except that the labels of their tracks are RGB and XYZ respectively. Point3 XYZ controllers can be used for functions such as Noise Strength, and the FFD modifier.
Example: To animate the background color of a rendered animation:
In the Track View hierarchy, expand the Environment track and then select Background Color.
On the Track View menu, click Controller > Assign and select the Color RGB controller.
Right-click one of the keys to display the Bezier Float dialog. Change the key values to 0, 400, and 0, respectively.
To see the background color change, move the time slider to the same frame as the key that is being adjusted and render the scene. To see the color change in an animated fashion, you must render the animation.
Although you can set values over 255 in the value field, the actual color value stops at 255.