Photoshop CS2 Bible
Color corrections can be exciting or mundane. Oftentimes the most practical modifications don't look like modifications at all. Consider Figure 11-1. The first example is of a distant cousin. Although an evocative photograph, the colors are bent a tad too far into the blue spectrum. (Fortunately, this problem can be easily fixed, as the rest of this chapter will demonstrate .)
So what we have is a beautiful image with technical shortcomings. What we decide to do with it is up to us. We can ignore the technical problems ” in fact, abandon all semblance of realism ” and enhance the otherworldly nature of the photograph by applying a color effect. The second example in Figure 11-1 shows the result of mapping the image to one of Photoshop's predefined gradients using Image Adjustments Gradient Map. But more likely, correcting the photograph is the path to take, in this case using Image Adjustments Curves and a bit of Unsharp Mask, as in the last example. Although the final example took more time to achieve, at first glance it doesn't look radically different from the original. But a close comparison reveals that the colors are much more true to life, and the focus is better. And where image correction is concerned , that's what ultimately counts.
A few words about color effects and corrections
Scans and digital photographs are rarely perfect, no matter how much money you spend on the hardware or service. They can almost always benefit from tweaking and subtle adjustments ” if not outright overhauls ” in the color department. Keep in mind, however, that Photoshop can't make something from nothing. In creating the illusion of more and better colors, most color-adjustment operations actually take some small amount of color away from the image. Somewhere in your image, two pixels that were two different colors before you started the correction are now the same color. The irony of color correction is that, even though an image may look 10 times better, it will in fact be less colorful than when you started.
Remembering this principle is important because it demonstrates that adjusting colors is a balancing act. The first nine operations you perform may make an image look progressively better, but the tenth may send it into decline. There's no magic formula; the amount of color mapping you need to apply varies from image to image. Our goal in this chapter is to give you the benefit of our hard-earned experience. If you take these recommendations ” use the commands in moderation , know when to stop, and save your image to disk before doing anything drastic ” you should be fine.
Using the adjustment dialog boxes
With the exception of the Auto commands covered in the next chapter, all the color adjustments discussed enable you to correct an image by entering values or making other changes inside a dialog box, like the one in Figure 11-2. Here are a few key points to file away in the back of your mind as you work:
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Turn on the Preview check box to see what you're doing. Only the Variations dialog box lacks a Preview check box. Otherwise, when turned on, you see the results of your changes in the image window. Assuming your computer is modern enough to provide the proper processing power, there is no reason on earth to turn this option off.
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To reapply the most recent adjustment settings, press Alt (Option on the Mac) when choosing the command. Again, the exception is Variations, which always remembers your last settings. In addition to Alt-selecting the command from the Adjustments submenu, you can also press Alt along with a command's keyboard shortcut. For example, Ctrl+Alt+U ( z +Option+U) brings up the Hue/Saturation dialog box with the last applied settings intact, assuming those settings were applied since you started up Photoshop.
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Save your settings. Many dialog boxes offer a Save button, which when clicked, will save your settings for later use. This is especially useful when correcting multiple images shot under similar circumstances. You can use the settings during a separate Photoshop session, or even e-mail them to a colleague to use on another computer. Macintosh users: Be sure to include a three-character extension (which Photoshop automatically recommends, assuming Append File Extension is set to Always in the Preferences dialog box) with the file name if you want to use the settings on a Windows machine.
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Alt-click the Cancel button to reset all options to their neutral settings. When you press the Alt key (or Option on the Mac), the Cancel button changes to Reset. This enables you to restore an image to the way it looked when you first chose the command, so that you can begin the adjustment process over again.
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Choose Edit Fade to temper an adjustment. As always, pressing Ctrl+Shift+F ( z +Shift+F) lets you fade the most recently applied operation, either by reducing its opacity or applying a blend mode. But the command only works immediately after applying an adjustment.
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When in doubt, use an adjustment layer. Chapter 8 recommended that you float an image to an independent layer before applying a filter, thus affording you the option to mix the filtered image with the underlying original. When applying color adjustments, this technique isn't necessary. That's because you can apply most of the essential color adjustment commands as independent layers . An adjustment layer is editable long after it's created, it may be turned on and off, and it can affect multiple layers at a time. The main difference is that, instead of choosing a command from the Image Adjustments submenu, you choose it from the adjustment layer icon at the bottom of the Layers palette, shown in Figure 11-3.
Figure 11-3: In addition to applying a static adjustment from the Image Adjustments submenu (left), Photoshop enables you to apply a dynamic adjustment layer from the Layers palette (right). Cross-Reference For complete information on these wonderful tools, read the section "Adjustment Layers" toward the end of this chapter.