After Effects supports both linear and radial gradients. With a linear gradient, you place your three colors along a linear axis, one after the other, with your chosen range of space between them.

How to Change the Shape and Gradient Colors in PowerPoint. Microsoft PowerPoint offers options for formatting a slideshow's objects. Shapes can receive a solid color, a pattern or a gradient whose ...

Fading color to black and white. Try dragging from corner to corner or top to bottom and see what you get—depending on your image, one gradient angle may look better than another.

For both solid colors and gradients, you can enter colors using their English HTML names or, better yet, any Hex code in the standard #123ABC format (a six-character code preceded by a # character).