Click something that should be neutral in color. It doesn't have to be mid-gray, just something that should be neutral. This reduces or eliminates any unwanted color cast in the image. If you don't like the result, click somewhere else in the image. Keep clicking until the colors in the image look right.
In Figure 5-11, the shadow under the bridge, the splash of water, and the weathered wood of the bridge itself provide excellent targets for the three eyedroppers.
Adjusting your curves without dieting
One step up from Levels in complexity, and about five steps ahead in terms of image control, is ImageOAdjustmentsOCurves (^+M/Ctrl+M). Like Levels, you use Curves to adjust the tonality of your image. But rather than a slider with three adjustment controls, the Curves dialog box offers you the chance to control different parts of the tonal range independently. (Curves also offers eyedroppers for tonal and color correction. They're used the same way you use the eyedroppers in Levels.)
At the very beginning of this chapter, I show you how a simple tonal adjustment could add some drama, some interest to a rather bland image. Figure 5-12 shows you the simple Curves adjustment that I applied to that image. Dragging the curve downward in the shadows makes them darker, dragging upward for the highlights makes them brighter. The mid-tones (that section of the tonal range between shadows and highlights) also gets lightened a bit in this adjustment.
When you first open the Curves dialog box, you see a graph with a diagonal line running from an anchor point in the lower left to another in the upper right. You click and drag that line up or down (not sideways) to add anchor points and make changes in the curve (and in your image). By default, the shadows are in the lower left, so dragging down darkens, and dragging up lightens. (See that two-headed arrow directly below the center of the graph? Click it to reverse the shadows and highlights in the Curves dialog box.) You can add more than a dozen anchor points to the curve — although you generally only need between one and three new points.
Most snapshots can benefit from a slight tweak in Curves. Click at the intersection of the first vertical and horizontal gridlines in the lower left (the quarter tones) and drag down slightly. The Input field should read 64, and the Output field should be somewhere between 55 and 60 for a shot that looks pretty good to start. Next, click at the intersection of the grid lines in the upper right (the three-quarter tones) and drag up slightly. The Input field should show 192, and the Output field can be anywhere from 195 to 205.
Both the Curves and Levels dialog boxes offer you the Load and Save buttons. If there's a correction that you'll use more than once, or a correction that needs to be precise time after time, use the Save button. Then, later, you can use the Load button to apply that adjustment to another image. If, for example, you used the wrong setting in your camera while taking a series of shots under the same lighting conditions, it's probable that they all need the same correction. Make the adjustment once, save it, and then apply it to the other images with the Load button.
If you want to correct a specific area in the image, hold down the mouse button and move the cursor into the image window (where it appears as the Eyedropper tool). You'll see a circle on the curve (like that near the middle of the curve in Figure 5-13), telling you where those pixels fall in the tonal range. To add an anchor point there, ^-click/Ctrl-click in the image window.
When your curve has multiple anchor points, the active anchor point shows as a filled-in square. Unselected anchor points are hollow squares. For precision, you can use the arrow keys on your keyboard to move the active anchor point, or you can type specific values in the Input field (starting position for the anchor point) and Output field (where you want the anchor point to go).
You have a couple of ways to customize the appearance of Curves, too. Click the button in the lower-right corner to toggle between the standard-size dialog box and a larger version. Option-click/Alt-click in the grid area to toggle between a 4 x 4 grid and a 10 x 10 grid. And, rather than clicking and dragging on the curve, you can activate the Pencil tool (shown in Figure 5-14) and draw your own curve by hand. When hand-drawing your curve, you've got the Smooth button available, too, to ensure that the transitions in your tonal adjustments are not too severe.
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