One of the magical things about personal computers is how they can help you create realities. This is also one of the most dangerous things about them.

Creating a reality can happen, among other ways, with computer-aided photography (also called digital imaging).

You start with a facsimile of reality—for example, a photo that you’ve taken with a digital camera or with a conventional film camera. You then digitize it with a scanner or with the help of a scanning service such as Kodak Picture CD (http://www.kodak.com/eknec/PageQuerier.jhtml?pq-path=9/511&pq-locale=en_US). Once it’s scanned, you bring the photo into your PC. That’s when the fun begins.

Most people who’ve been around computers for any time know the ways you can enhance, correct, or change a photo with an image editing program. The leading high-end program is Adobe Photoshop (http://www.adobe.com/products/photoshop/main.html); it has been the leader since it was released in 1990. As Wikipedia’s excellent entry on Photoshop (http://en.wikipedia.org/wiki/Adobe_Photoshop) points out, the program has had such a cultural impact that many people now use the neologism “photoshop” to mean digitally enhancing a photo regardless of the program used.

Though impressively versatile, Photoshop remains pricey: The latest version, CS2, has a street price of just under $600. A more appropriate program for nonprofessional users is Photoshop Elements. The latest version, 4.0, is priced just under $90; a free “tryout version” is available for downloading at Adobe’s Web site.

Another popular program is Corel Paint Shop Pro (http://www.corel.com/servlet/Satellite?pagename=
Corel3/Products/Display&pid=1047025487586). You can find the latest version, X, for slightly under $110.

These and similar image editing programs are so powerful that you can easily create a false reality. Regardless of which program you use, the single most important thing to remember is to avoid overdoing it, said Glenn Honiball (http://www.retouch.ca), a professional graphics artist based in Toronto and the author of the new book Commercial Photoshop Retouching.

One of the more controversial, and embarrassing, examples of this was during the O.J. Simpson affair, when both Time and Newsweek used the same mug shot of Simpson on their covers. But Time darkened Simpson’s skin, possibly to make him look more sinister (or at least more dramatic). In the eyes of many, this was a venal attempt at digital sensationalizing, pandering, and exploitation.

More commonly, those working with photos in ad agencies or other business settings make people look too good. The models end up with perfect white teeth and sparkling eyes, have no hair out of place, and appear without a wrinkle, freckle, mole, or pimple.

“Retouching works best,” said Honiball, “when people looking at a photo say, ‘I don’t know what you’ve done to it.’ That’s your best compliment. A retouched photo shouldn’t look retouched.”

Retouching is especially helpful when you’ve made a mistake in taking the photo involving the lighting, the camera settings, or the way you’ve composed the shot.

Perhaps the photo exhibits a false orange cast, depicts a tree in the background that looks as if it’s growing out of your subject’s head, or shows a distracting trash can in an otherwise beautiful vacation picture. Perhaps your subject’s wrinkles look harsher or his teeth yellower than in reality.

It’s always best to avoid mistakes in the first place. To prevent off-color photos when shooting inside, change your digital camera’s “white balance” setting, use special “daylight-balanced” light bulbs, or place your subject by a window.

To prevent the devilish “red eye” problem if you use a flash, use your camera’s red-eye setting, turn up the lights, or tape a small piece of tracing paper over the flash to diffuse its light.

When composing a shot, fill the camera’s LCD screen or viewfinder with what you want to appear in your photo by moving close to your subject or using the camera’s zoom. Avoid situations where objects such as telephone poles are directly behind your subject’s head.

Unless you have a high-end digital camera, avoid subjects such as trees that consist of intricate details. Film cameras still work best in these situations. In general, avoid a background that’s overly cluttered or distracting. People and other subjects that clearly stand out from their backgrounds work best with digital cameras.

Image editing programs not only let you correct mistakes, they also let you get creative. You can combine elements from different shots to construct a montage or impart jazzy special effects, including those that make a photo look like a watercolor or oil painting.

Image editors provide lots of tools, and one of the tricky things in using them is choosing the most appropriate tool. Practice makes perfect, said Honiball.