ADDING CONTRAST: Photoshop CS4 and CS5 show a histogram behind the curve. If your histogram doesn’t touch the edges, add contrast by moving the small black and white triangles inward to your histogram’s edge. This makes the angle of the curve line steeper. Note: Use this method only when your histogram doesn’t touch the edges. If you do it on an image with a good histogram, you’ll end up clipping your highlights and shadows.