Epson ES-800C Supplementary Manual page 8

200
600 dpi/133 line screen
You'll also notice that if you scan a color image at
600 dpi, the printed result is not much different
from what it is if you scan the same image at 200
dpi, because all printers and printing presses
reproduce the image as a series of dots and have
their own maximum resolution.
Here are two images, one scanned at 200 dpi, one
at 600 dpi, output on the same device. Can you tell
the difference?
An easy way to determine the best resolution for
your intended output is to find out the lines per
inch (lpi) capability of your printer and multiply
it by 1.5. For example, a typical magazine printing
press prints at 133 lines per inch. To tailor your
scanned image for the best possible results
on this press, you multiply the lines per inch
(133) by 1.5:
133 x 1.5 = 199.5
In this example, the resulting number (200) is the
optimum resolution for the scan. (If you regularly
use a service bureau to print your scanned materials,
you can also ask the printer for the lpi of his
particular printing press and to suggest resolutions.)