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Playing with Photoshop's Auto Color
If you're like me, you tend to want as much control as possible when editing images in Photoshop. For this reason, you may have avoided the various "auto" features Adobe thought everyone would love. Or at least I did. But it's time to change that. Sometimes, Auto may be just what an image needs.
There are three "auto something" tools located on the Image >> Adjustments menu: Auto Levels, Auto Contrast, and Auto Color.
Auto Levels will examine an image and locate the brightest and darkest points in it. By design, it will clip a small degree of highlight and shadow detail, mapping a point that is almost the brightest to white and one that is almost the darkest to black. This will definitely give you a lot of contrast, but you may also end up with a color cast since each channel is examined individually. If your image had an unintended color cast, you may be able to easily get rid of it with Auto Levels, but it is at least as likely that the resulting color shift will be unwelcome. If you don't, simply undo it using the History Palette.
Auto Contrast works pretty much the same as Auto Levels, but it works on all channels together to avoid color shifts. You may or may not like the results of course. Still, it's easy enough to try Auto Contrast to see what you get. It will still clip a small amount of highlight and shadow pixels to be sure it finds bright and dark regions that are truly representative.
Photoshop has had Auto Levels and Auto Contrast for quite some time now, but Auto Color was new with version 7. Now that CS3 has been released, I guess even that qualifies as a long time. But being newer, it represents Adobe's attempt to make a better version of the original two "auto" tools. It will examine an image in order to identify highlight, shadow and mid-tone regions. Once it does, it will remap the white point and black point of all three channels together, the same way Auto Contrast does. But it then looks at the mid-tones of each channel and neutralizes each to a value of 128 in order to correct for color casts. Auto Color may still not give you what you want, but this way of doing things seems to yield a higher percentage of successes than to Levels and Contrast.
Sometimes, even if you like the results of Auto Color, you may find them a bit overdone. To tone things down, start by creating a copy of your image on a layer before applying Auto Color. You can then fade in the effect to the degree desired using the Opacity slider. You can do this even without the extra layer if you go to Edit >> Fade Auto Color after applying Auto Color, but you get only one shot at this. You must fade the effect immediately after applying Auto Color, and if you later decide to fade it even more (or less), you are out of luck. This is one place where adding an extra layer is worth it.
Cranes at Bosque del Apache |
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Adjusted with Auto Contrast |
Dawn at Reflection Lakes, Mt. Rainier National Park |
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Auto Color doesn't always work |
All three "auto" adjustments can sometimes save an image you can't come up with any other way to correct. And being quick and easy to use, they can be worth trying when you are stuck. Sometimes, they can create great new versions of images in ways you hadn't even thought of. But if it works, go with it.
Next week, we'll look more at Auto Color, and at how you can turn it into a "semi-auto" mode and take at least a bit more of the control yourself.
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