- If you go through life convinced that your way is always best, all the new ideas in the world will pass you by.
- —Akio Morita, founder of Sony
When you work with grayscale images, your adjustments and corrections are limited to only tonal adjustments—that is, changes to the brightness and contrast of the image. When you work with color images, you also have to worry about hue, saturation, and the other properties of color.
Photoshop provides several tools for making tonal adjustments, and we'll look at all of them. You can use these tools for correcting and adjusting both grayscale and color images.
With all previous versions of Photoshop, it was safe to say that you should never use the Brightness/Contrast dialog box to make tonal adjustments. This was because Brightness/Contrast used to adjust the entire tonal range of the image by equal amounts, which made it difficult to adjust one part of the image—say, the shadows—without screwing up another part of the image, such as the highlights.
With CS3, Adobe has reengineered the Brightness/Contrast dialog box and turned it into a very useful, very powerful tonal adjustment tool.
You'll find the Brightness/Contrast adjustment by choosing Image > Adjustments > Brightness/Contrast. The dialog box is very straightforward (Figure 4.1). By sliding the Brightness slider back and forth, you can make your overall image brighter or darker. In general, the Brightness slider protects your shadow areas—it won't usually let you underexpose them too far. This means that you need to keep a very close eye on the highlights in your image. As you adjust the slider, be careful that you don't let the highlights overexpose and blow out to complete white (Figure 4.2).
Figure 4.1 The Brightness/Contrast dialog box.
Figure 4.2 As you slide the Brightness slider to the left or right, your image becomes darker or lighter. (©2007 Andy Katz)
The Contrast slider increases contrast in your image by brightening the light parts and darkening the darker areas (Figure 4.3). The overall effect is an image with more "pop" and better detail.
Figure 4.3 With the Contrast slider you can add more punch to your images.
Moving the slider to the left lowers the contrast, resulting in a flatter image (Figure 4.4).
Figure 4.4 The Contrast slider can also be used to pull contrast out of an image.
Brightness/Contrast is not the most refined tool, but it can be a great place to start if you're new to Photoshop.