Posted By:
D. BerginReproducing printed images (as second- or third-generation images) results in an obtrusive moiré effect (that diagonal-checkerboard-like pattern seen on badly reproduced and degraded photos), and there'd be a noticeable loss in clarity and quality of the image.
If your scanner software has a "descreen" option you can pretty much solve the moire effect problem with printed type photos. It won't magically turn them into real photos but will give them a much smoother look.