Access Digital Photography

If you’ve got an image that lacks contrast, you can easily add it in Photoshop. The traditional approach would be to use the Brightness/Contrast command under the Adjustment menu, or to add a Brightness/Contrast adjustment layer to the image. The problem with either method is the adjustment is linear to all pixels. I use a method that increases contrast by darkening the shadows and brightening the highlights.

1. Click the Adjusment Layer icon at the bottom of the Layers palette, and choose Curves. This adds a Curves adjustment layer to the image. The reason for using an adjustment layer instead of the Curves command is that an adjusment layer does not alter the background layer. It simply does the calculations and applies them to the image. You can modify the adjustment layer at any time by double-clicking its icon to reopen the adjustment layer dialog box. You can also vary the opacity of the layer to decrease the effect, and change the layer blend mode as well.
2. Add three points to the adjustment curve; one at the lower third of the curve, one in the middle of the curve, and one at the upper third of the curve. Don’t worry if your placement is not exact. You’ll be entering values in each point’s Input and Output text field.
3. Click the bottom point and enter a value of 60 in the Input text field, and a value of 50 in the Output text field. This darkens the shadow areas of the image.
4. Click the middle point and enter a value of 128 in the Input text field, and a value of 128 in the Output text field. That keeps the midtones at their current level of brightness.
5. Click the top point and enter a value of 190 in the Input text field, and a value of 200 in the Output text field. This brightens the highlights of the image.
6. Click OK to apply the Curves adjustment layer to the image. At this point, you’ll probably notice a color shift in the image.
7. Change the blend mode of the Curves adjustment layer to Luminosity. This blend mode applies the adjustment layer to the image without causing a color shift.

The image before adding contrast with a Curves adjusment layer.

The image after adding contrast with a curves adjustment layer.

No pixels were harmed or destroyed during the creation of this tutorial.

This entry was posted on Thursday, August 3rd, 2006 at 8:27 pm and is filed under Photoshop Tips and Tricks. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.