Does anyone know of a good resource where I can find more information about scanning at the optical scan rate? I know if you scan at such a rate the image will be as pure as possible and you won't introduce interpolation artifacts and possible moire' patterning.

Where can I also find a chart listing the approximate dpi output to the following media: television, newsprint, monitor, magazine, poster, and prints. (I know dpi is not defined that way when it comes to tv or the monitor.)

The reason I'm asking is that I have a "professor" who doesn't understand imaging mechanics, and I can't find clear information in which to correct his misconceptions. Can anyone help me?

-- Sue Bald (destiny3@ix.netcom.com), June 09, 2000

Answers

Try Scantips Website as a starting point. Although it may be too simple for a professor to understand!

By "the optical scan rate" I take it you mean the native optical resolution of a scanner, without interpolation or pixel averaging? Using that particular resolution won't automatically get rid of Moire patterning. That's dependent on the dot screen and angle of the half-tone original, and even how it's positioned on the scanner is critical. Blurring, averaging or use of a "despeckle" filter, and trial and error with the scanning resolution are the only ways to minimise moire patterns (and you shouldn't be copying from printed material without permission anyway) ;^)

-- Pete Andrews (p.l.andrews@bham.ac.uk), June 09, 2000.