Digital Photography

Scanning is the bridge that carries film-based negatives and transparencies or printed images into the digital world. The process converts all color, brightness, and contrast information into digital data for your software to use. The quality of the scanner and the skill with which it is used are the key factors that determine the quality of the digital information and, hence, the quality of the image you have to work with .

You can think of scanning as a three-stage process:

Gather together originals for the job. You may have to make prints of family portraits, say, or collect images for your club's website.

Next is the actual scanning. To do this, the scanner makes a prescan to allow you to check that the original is correctly oriented, or to set the scanner to scan only as much of the original as you want, or to set the final image size and resolution. You then make the real scan and save the result onto the computer's hard disk.

The final stage is basic "housekeeping"put your originals somewhere safe, somewhere you can readily find them again, and, if the work is critical, create a backup copy of the scans.

To get the most from scanning, it is a good idea to follow some commonsense procedures designed to help streamline your working methods.

Plan aheadcollect all your originals together before starting.

If you have a lot of scans to make from a variety of different types of original, sort them out first. If, for example, you scan all black and white originals and then all color transparencies you will save a huge amount of time by not having to alter the scanner settings continually.

Scan landscape-oriented images separately from portrait-oriented ones. This saves you from having to rotate the scans. And you will minimize visits to dialog boxes if you classify originals by the final file size or resolution you want.

If you are using a flatbed scanner, clean your scanner's glass plate, or platen, before starting.

Make sure originals are clean. Blow dust off with compressed air or a rubber puffer. Wipe prints carefully to remove fingerprints, dust, and fibers.

Align originals on the scanner as carefully as you can: realigning afterward may blur fine detail.

Scan images to the lowest resolution you need. This gives you the smallest practicable file size, which, in turn, makes image manipulation faster, takes up less space on the hard disk or other storage media, and gives quicker screen handling.

Use file names that are readily understood. A file name you choose today may seem obscure in a few months.

When scanning, crop as much extraneous image detail as is sensible in order to keep file sizes small, but allow yourself room to maneuver in case you decide to crop further at some later stage.

You may need to make your output image very slightly larger (say, an extra 5 percent all around) than the final size. This may be essential if, for example, you want your image to "bleed," or extend to the very edge of the paper so that no white border is visible.