Photoshop CS3: Adjusting Color | Page 3
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Adjusting with the Color Balance Dialog Box
To really understand color balance, you have to look at the color wheel. In case you don't remember the order of the color wheel, just flip to the Color Gallery and take a look at the example provided.
Every color on the wheel has an opposite. If you follow the line from one color through the center of the wheel, you reach its opposite. Cyan is opposite to red; green is opposite to magenta; and yellow is opposite to blue. When you use the Color Balance dialog box to adjust colors in a picture, you're adding more of the color opposite to the one you want to reduce. Increasing the cyan reduces red. Increasing red reduces cyan, and so on, around the wheel.
Figure 5.9 shows the Color Balance dialog box. Color Balance is intended to be used for general color correction rather than for correcting specific parts of an image, although you can use it that way by selecting only the part to correct. It's especially helpful if you have a scanned image that is off-color, such as an old, yellowed photograph. It's very simple to apply the Color Balance tools to remove the yellow without altering the rest of the picture.
Move the sliders in the direction of the color you want to add.
In addition to Color Balance, you can use the sliders to adjust tone balance. As with the Variations dialog box described earlier, you can concentrate your efforts on adjusting shadows, midtones, or highlights by clicking the appropriate button.
Try It Yourself: Apply Color Balance
Color balance can rescue pictures that have faded, and it can turn red roses blue or blue ducks red. It's fun to play with.
Select the image or portion of the image to correct. Open the Color Balance dialog box by choosing Image>Adjustments>Color Balance or pressing Cmd-B (Mac) or Ctrl+B (Windows).
Choose Shadows, Midtones, or Highlights. Generally it's advisable to start with midtones, if you are correcting the whole picture, because the midtones comprise 90% of an image.
Check Preserve Luminosity so that you don't change the brightness of the image as you shift colors. If maintaining the brightness isn't important, don't enable the check box. Be sure to select Preview so that you can see how your changes affect the image.
Move the sliders to adjust the colors. The numbers in the boxes change to indicate how much of a change you are making. They range from 0 to +100 (toward red, green, and blue) and from 0 to 100 (toward cyan, magenta, and yellow).
Adjust the shadows and the highlights; repeat the corrections until the image looks correct to you.
Click OK to apply the changes.
If Color Balance doesn't seem to do what you want, undo it.
Adjusting with the Hue/Saturation Dialog Box
The Hue/Saturation dialog box is a very powerful tool with a slightly misleading name. Sure, it lets you adjust the hue (colors in the image) and the saturation (the intensity of the colors), but it also gives you control over the lightness.
First, look at the controls in the Hue/Saturation dialog box (see Figure 5.10). The first pop-up Edit menu lets you select either a single color to adjust or the Master setting, which adjusts all the colors in the image or selection at once. For now, work with the Master setting. Check Preview so that you can see the effects of your changes in the picture you're working on.
Small adjustments to Lightness and Saturation are usually all that's needed.
There are three sliders: Hue, Saturation, and Lightness. The Hue slider moves around the color wheel. With Master selected, you can move all the way from red (in the middle of the slider), leftthrough purple to blue or blue-greenor right through orange to yellow and to green.
The Saturation slider takes you from 0%, in the center, to 100% saturated (pure color, with no gray) on the right, or 100% unsaturated (no color) on the left.
The Lightness slider lets you increase or decrease the brightness of the image, from zero in the center, to +100 on the right, or 100 on the left.
As you move these sliders, watch the two spectrum strips at the bottom of the window, as well as the image itself. The upper strip represents the current status of the image, and the lower one changes according to the slider(s) you move. If you move the Hue slider to +60, for example, you can see that the reds in the picture turn quite yellow and the blues turn purple. In effect, what you are doing is skewing the color spectrum by that amount. If you move the Saturation slider to the left, you'll see the lower spectrum strip become less saturated. If you move the Lightness slider, you'll see its effects reflected in the lower spectrum strip as well.
Light Is Bright - Lightness is technically the same as brightness. The Hue, Saturation, Brightness (HSB) color model uses these terms to define a color, as opposed to the RGB and CMYK models, which define it as percentages of the component primaries. These primaries, of course, are red, green, and blue for RGB, and cyan, magenta, yellow, and black for the CMYK model.
Instead of selecting Master from the pop-up menu, if you select a color, the dialog box changes slightly, as you can see in Figure 5.11. The Eyedroppers are now active, enabling you to select colors from the image, and adjustable range sliders are centered on the color you have chosen to adjust. You can move these back and forth to focus on as broad or narrow a range within that color as you want. This might not seem like a big deal, but it's really very powerful, especially if you want to create a pink tiger, or maybe a blue one.
Click and drag to move the sliders. You can extend the range of colors to be affected by dragging the edges of the range selector between the two color bars.
Try It Yourself; Adjust an Image Using the Hue/Saturation Dialog Box
This powerful tool is best applied in small doses.
Open the dialog box by choosing it from the Image>Adjustments menu or by pressing Cmd-U (Mac) or Ctrl+U (Windows). Click Preview to see your changes as you make them.
Use Master (the default setting) to adjust all the colors, or use the pop-up menu to select the color you want to adjust.
Create the desired adjustments by moving the three sliders to the left or right. The following are some tips for getting the effect you want:
Drag the Hue slider left or right until the colors look the way you want. The numbers displayed in the Hue text box refer to the degree of rotation around the color wheel from the selected color's original location.
Drag the Saturation slider left to decrease the saturation of the colors and right to increase it.
Drag the Lightness slider to increase or decrease the lightness of the image.
Click OK when you're done.
Adjusting with the Brightness/Contrast Dialog Box
Photoshop CS3's Brightness/Contrast function isn't new, but it's definitely improved. If you need to make a simple adjustment to the tonal range of an image that scanned too dark, the Brightness/Contrast dialog box (choose Image>Adjustments> Brightness/Contrast) seems like an easy way to accomplish just that (see Figure 5.12), right? However, in all previous versions of Photoshop, Brightness/Contrast applied the same correction throughout the image, meaning that if you made the image brighter, you ended up with gray shadows and stark white highlights along with your nice, bright midtones. Now, however, that's all changed; Brightness/Contrast now separately corrects the dark, middle, and light values.
Use the sliders to adjust the brightness and contrast.
Although the Brightness/Contrast dialog box doesn't give you the same control that you would have if you made the adjustments using Levels or Curves, or even the Variations dialog box, it's quick and easy. Sometimes it's all you need. Many images are improved by just raising the brightness and contrast by a couple of points. As always, be sure to check the Preview box so that you can see the effect your changes have on the image.
Dragging the sliders to the right of the middle point increases brightness or contrast. Dragging them to the left decreases it. If you're not happy with the results you get with this tool, undo your changes and use the Variations dialog box, or Levels or Curves, to adjust the brightness and contrast.
If you encounter a situation in which you want to make everything in your picture lighter or darker, you can revert temporarily to the old version of the Brightness/Contrast function by clicking the Legacy check box.
Correcting the Shadows and Highlights
One of the coolest features in Photoshop is the Shadow/Highlight dialog box. It allows you to control the amount of highlight and shadow on an image without changing the contrast. If you apply it to the tiger photo, you can let her sit in deeper shade without changing the intensity of her stripes, or turn up the sunlight without washing the color out of her pale cream fur. Be sure to check the Show More Options box to open the full set of sliders, as shown in Figure 5.13. See the corrected tiger in Color Plate 5.12, and compare her to the original picture in Color Plate 5.6.
Experiment with these sliders on both high-contrast and low-contrast images.
When a photographer wants a special effect, he or she might use a colored filter over the camera lens. With this feature, you can do the same thing to any image, whether from a camera, scanned, or created from scratch. In Figure 5.14, I have expanded the list of filters so you can see the many options available. Serious photographers will recognize the numbers after the warming and cooling filters, because they are the same as on the glass filters you might buy at a good camera store. Use the slider to control the strength of the filter. Typically, you would use no more than 1020% to warm up daylight or to take the excess yellow out of an indoor shot. To open the Photo Filter dialog box, follow this path: Image>Adjustments>Photo Filter.
You can also use any color as a filter.
Other Menu Options
It's almost time to wrap up your tour of the Adjustments submenu. Here's a look at a few commands we haven't covered yet that you might find useful.
Auto Contrast is occasionally helpful. It automatically maps the darkest and lightest pixels in the image to black and white, causing highlights to appear lighter and shadows darker. It might not be the best way to make the necessary adjustments, but, if you are in a hurry, it can save you some time.
There's another Auto tool: Auto Color. This tool, quite simply, analyzes the color in an image and makes an educated guess as to what it should be. If you're easily satisfied, it might be all the correction you ever need. As for me, I like things perfect, and Photoshop's sense of color is often different than mine.
Desaturate removes all of the color from an image, without changing the color mode. If you want a quick look at how something will reproduce in black and white, this is the command to use. Then, simply undo it to go back to the colored version.