Tuesday, October 06, 2009


To adjust the brightness and contrast of a black and white image, or to adjust the brightness and color balance of a color image, Layer>New Adjustment Layer>Levels. "Levels" opens a complex window with several buttons and a graph. The graph is called a histogram and is showing the tonal range of the image with the shadows on the left, the midtones in the middle and the highlights on the right. The 3 little triangles running along the line below the histogram are referred to as the input sliders. The color of each one (black, gray and white) shows what part of the tonal range that each one represents. There are 3 boxes above the histogram showing the numerical representations of every tone in the image. 0 is jet black and 255 is paper white.

To the right of the input slider bar appear 3 eyedroppers. Notice once again that they are colored black, gray and white. Click on the white one which is the one on the right. When you move the cursor into the image you will notice it has changed from an arrow (or whatever else was the previous cursor shape) to an eyedropper. Click on the lightest area of significance. In other words, don't choose something like a bright white reflection off of a mirror or something similar. The image should look somewhat different after doing this and the histogram should change. Do the same with the shadows using the eye dropper on the left. For the midtones move the midtone input slider to the left to lower the contrast and to the right to increase the contrast. Ignore the midtone eye dropper. Click on the OK button to complete the procedure and then save the image.

© 2009 Paul Light all rights reserved


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