The Gradient Map adjustment replaces the tonal values of the image with the colors supplied by a gradient. It's a great tool for generating special color effects. In addition, the Gradient Map adjusts the active image's colors to the colors of the selected gradient; taking the shadows of the image and mapping them to one endpoint of the gradient, and the highlights to the other point.
Image menu, point to
Adjustments , and then click
Gradient Map .
Gradient Used For Grayscale Mapping list arrow to adjust the gradient.
Dither or
Reverse check boxes for the Gradient Options.
Preview check box to view changes to the active image.
OK .