By Lesa Snider, iStock evangelist and author of Photoshop CS5: The Missing Manual
Photoshop’s Gradient tool is incredibly useful. You can use it to fill a layer, selection or text with color, or inside a layer mask to produce faded color effects and collages.
For example, instead of painting on a layer mask with a black or white brush—wherein black conceals and white reveals—use a black-to-white gradient.
Here are two ideas to get you started: 1) Faded color to grayscale. A Black & White Adjustment layer is a great way to turn a color photo into black and white. Choose Layer > New Adjustment layer > Black & White and then use the Gradient tool inside the included layer mask to make the color fade softly into grayscale; 2) Solid color fade. Fading a solid color onto one side of a photo creates a nice spot for text. Choose Layer > New Fill Layer > Solid Color and then use the Gradient tool in the included mask to make the color fade into the photo.
That’s all there is to it!