Do your digital photos look flat and dull? A bump in contrast will often give them the life they need. The Levels feature offers a simple way to increase contrast. In the Levels dialog box, move the black and white input sliders in toward the middle until they just touch the edges of the histogram curve. This remaps the black and white points in the photo, turning the darkest pixels black and the brightest pixels white. Contrast refers to the difference in degree between the lightest and darkest tones in a photo, so this technique does increase contrast. The problem is that as more pixels are pushed to black or white, you can lose image detail in the shadows and highlights. This is called clipping. What to do?

Try using Threshold View to control exactly which pixels are clipped. To see your image in Threshold View, hold the Option key (Mac) or the Alt key (Windows) as you drag the white input slider toward the middle. Stop dragging when you see small clumps of white or color in the image. (The color of the clumps indicates which channels are being clipped.) The larger the clumps, the more detail will be lost. Repeat with the black slider, stopping when you see small clumps of black or color. Also, make your Levels adjustment in an adjustment layer. That way you can always go back and edit the adjustment to control clipping.