Step 4: Add Contrast using Image: Adjustments: Curves

The Curves command is one of the most powerful features of Photoshop. It allows you to change specific ranges of colors while leaving others untouched. For example, in Step 3 we adjusted the shadows and highlights. They are as we want them to be and we don't want to change them. In this step we will add contrast to the image by adjusting the quarter tones and three quarter tones, while leaving the midtones, shadows and highlights untouched.
Step 1: Choose Image: Adjustments: Curves. The Curves dialog box opens. At this point there are no curves, just a straight line. Curves are added by clicking on this line to add control points, then dragging the points upwards or downwards.

Step 2: Click the line in the Curves palette where it intersects with the grid in the upper right and lower left, as shown in the picture
Step 3: Adjust the quarter tones. Click the upper control point. Hit the Up arrow until you begin to see a contrast.

Step 4: Adjust the three-quarter tones. Click the lower control point and click the down arrow until the contrast increases.

Step 5. Working a small amount at a time, clicking back and forth between control points, adjust the contrast until you are pleased with the results.

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