Adjusting by Eye with Variations
The most obvious way to make a color adjustment is to compare before and after views of an image. In Photoshop, the tool for doing this is called Variations. It's the last item on the Image>Adjustments submenu. Variations combines several image adjustment tools into one easy-to-use system that shows you thumbnail images that are variations on the original image. You simply click the one that looks best to you. You can choose variations of hue and brightness and then see the result (which Photoshop calls Current Pick) compared to the original.
Figure 5.2 shows the Variations dialog box. (See it in color in the color insert.) When you first open it, the Current Pick is the same as the original image because you haven't yet made changes. You can set the slider to the left (Fine) or right (Coarse) to determine how much effect each variation applies to the original image. Moving it one tick mark in either direction doubles or halves the previously selected amount. The finest setting makes changes that are so slight as to be almost undetectable. The coarsest setting should be used only if you're going for special effects and want to turn the entire picture to a single color. The default (middle) setting is the most practical for normal adjustments.
Figure 5.2 The seven thumbnails at the lower left adjust hue, whereas the set of three on the right side adjusts brightness.
Adjusting Shadows, Midtones, Highlights, and Saturation
When you use Variations to adjust a color image, you have the option of individually adjusting shadows, midtones, highlights, or overall color saturation. Shadows, midtones, and highlights are Photoshop's terms for the darks, middle tones, and light tones, respectively, in the picture (or what would be black, gray, and white in grayscale). When you correct them with Variations, you change the color (hue) of the shadow, midtone, or highlight. Saturation affects all of them at once, increasing or decreasing the intensity of the color, although not changing it.
When you choose Shadows, Midtones, or Highlights in the Variations dialog, you adjust the hue and brightness of only that part of the picture. The advantage here is that you can adjust the midtones one way and the highlights or shadows another way, if you choose. Each setting is independent of the others, and you can, for example, set the midtones to be more blue, thus brightening the sky, yet still set the shadows to be more yellow, offsetting the blueness that they possess inherently.
When a highlight or shadow value is adjusted so much that it becomes pure white or pure black, that's referred to as clipping. Clicking the Show Clipping box displays a neon-colored preview of areas in the image that will be clipped by the adjustment, so that you can try to minimize the amount of clipping that takes place. Clipping doesn't occur when you adjust midtones.
Remember, as you learned in Hour 4, "Specifying Color Modes and Color Models," hue refers to the color of an object or selection. Brightness is a measurement of how much white or black is added to the color.
Choosing Saturation changes the strength of the color in the image; the setting choice is simply for less or more color strength. In Figure 5.3, we're adjusting the saturation of this photo. Remember that you can apply the same correction more than once. If, for instance, less saturation still leaves more color in the image than you want, reduce the saturation again to get even less. (Don't confuse saturation with brightness. Saturation changes the amount of color. Brightness adds light.)
Figure 5.3 Less saturation gives you a duller image. More saturation gives you a more intense one.
Saving and Loading Corrections
Two other buttons appear in this dialog box, and in the other adjustment dialog boxes as well. These are the Load and Save buttons. They can save you a lot of time and effort if you have a whole series of pictures that need the same kind of corrections. Perhaps you used your digital camera to shoot several outdoor pictures with the same lousy light conditions. Maybe your scanner tends to make everything a little more yellow than you want. After you determine the settings that correct one picture perfectly, you can save those settings and then load them each time you want to apply them to another picture.
Click the Save button, and you'll see a typical dialog box that asks you to give your settings a name. You might call them foggy day fix or scanner correction. Then, when you need to apply them to another picture, use the Load button to locate and open the appropriate setting file, and your corrections will be made when you click OK in the dialog box.