(Dos & Don'ts)
Scanners normally allow you to scan images at varying resolutions.
The resolution is the amount of information the scanner picks up from
your photo. The higher the resolution, the more information. Because
of this, you might think that scanning a photo at a higher resolution
will give you more detail on your photo but this is not the case.
Your computer creates an image for output to print by creating 256
shades of grey for a black and white photo and 256 shades each of
Cyan, Magenta, Yellow and Black for color. To create these 256 shades,
your computer only needs a specific amount of information. The amount
of information needed is dependent upon the final "screen ruling"
that the printer will be using. If you scan anything at a higher resolution,
your computer uses only what it needs. Any higher resolution just
makes your file needlessly bigger, increasing the amount of time your
computer uses to process the file.
If you're planning on scanning type, that's a little bit different
than scanning a photo. Type requires more resolution than a photo
does. This is because a photo is created using the halftone process
which uses a dot pattern. Type, on the otherhand, needs more information
to create the structure of each letter. This is especially true
when you're scanning small type. I would suggest a minimum of 600
dpi when scanning type, especially if it is large type. With smaller
type and type with fine serifs, you could try scanning at 1200
dpi to hold more detail. Again, try to scan the type at a size close
to what it will be in your document to minimize file size. Be sure
to save the resulting file as "bitmap" and not "grayscale".