Do you have some near-perfect digital photographs that are marred by overexposure, underexposure, or low contrast? If you're itching to fix them, but reluctant to muck about with Adobe Photoshop's Curves and other manual adjustments, Photoshop also offers some jiffy fixes.
Called Layer Blending modes, these use math to combine the pixels of one layer with the pixels of an underlying layer to create an improved image. First step: Duplicate the image layer, which stacks your picture on top of itself. Then click on the drop-down menu in the upper left corner of the Layers panel to change the blend mode from Normal to one of the following:
Multiply: This darkens images and increases highlight contrast, just what you want for an overexposed photo. It multiplies each layer's pixel values together.
Screen: Basically the inverse of Multiply, this lightens images and increases shadow contrast, good for underexposed photos.
Overlay and Soft Light: These, in effect, multiply the shadows and screen the highlights, which increases contrast. Soft Light is a weaker version of Overlay.
You control the degree of the blend effect by adjusting the opacity of the upper layer-the lower the percentage, the more transparent the layer. When you get the look you want, merge the layers and you're done. Duplicating and blending layers takes only a few keystrokes, so it's well worth trying for quick fixes of your photographs.
