The Photoshop 6 Gradient tool enables you to fill a selection with a fountain of colors that starts with one color and ends with another. By default, the two colors are the foreground color and background color.

But Photoshop can do more than create simple two-color blends. You can create custom gradients that blend a multitude of colors and vary from opaque to transparent throughout the blend. Photoshop has five gradient types: Linear, Radial, Angle, Reflected, and Diamond. And the Options bar offers settings that enable you to play with blend modes, opacity, and reversing colors.

Press Shift+Right-click (Shift+Control+click on a Mac) to bring up the gradient palette right under your cursor for quick and easy selections.