I just bought a new scanner that gives me a choice to scan images as 16-bit or 8-bit images. Which should I choose?
Depends. If you're interested in maintaining the highest possible quality, scan at 16-bit. The good news is Photoshop CS2 can handle these high bit-depth images including most of the major retouching tools. The bottom line:Changes made to 16-bit images are less damaging than working on a straight 8-bit version. At the higher bit-depth, image can be manipulated in finer increments ultimately yielding better results.
A familiar retouching rule is to work on images that are physically larger than the finished size. When you reduce the file size, the retouching will be less noticeable. The same holds true for bit depth. When you're satisfied with your work, reduce the bit depth to the standard 8 bits/channel too. Unfortunately, not every image editing app can handle the 16 bit images.