Chapter 5. Optimizing Grayscale Images
iStockphoto.com/guyerwood
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 inexperienced users first try to adjust a grayscale image, they usually look for something familiar and easy, and the Brightness/Contrast dialog box is frequently where they end up (Figure 5.1). With a mere flick of the mouse, they can dramatically change their image. Big results, little effort. At first glance, the Brightness/Contrast dialog box seems to hold great promise. But does it really do the job?
Figure 5.1. The Brightness/Contrast dialog box.
If you were to compare images adjusted with Brightness/Contrast with the images you see in high-end magazines and brochures, you'd notice that the quality of the Brightness/Contrast images is inferior (Figures 5.2 and 5.3). Why? Because the Brightness/Contrast dialog box adjusts the entire image an equal amount. So, if you decide to increase the overall brightness of an image until an area that was 10% gray becomes white, then areas that are black will also be changed the same amount and become 90% gray. Using controls like these, it is extremely hard to achieve professional quality. When you correct one problem, you usually introduce another.
Figure 5.2. Image optimized using Brightness/Contrast. (©2005 Andy Katz)
Figure 5.3. Image professionally optimized.
Common adjustment complaints include
 | To reset sliders to their default positions, hold down Option (Mac) or Alt (Windows) and click on the Cancel button, which has temporarily become the Reset button. Or, you can type Option-Command-. (that's a period) on the Mac. If you have a color original that will be reproduced as a grayscale image, be sure to scan the original as color and then convert it to grayscale in Photoshop. Also, be sure to check out Chapter 10, “Color Manipulation,” where you'll learn how to produce a higher-quality grayscale conversion. |
Images appearing flat (lacking contrast)
Images printing overly dark
Blown-out detail in the highlights (bright white areas in the middle of people's foreheads)
Lack of detail in the shadows
All of these problems—and others—can be solved in one dialog box.