Canon ColorPASS-Z5000 Color Manual page 189

A
A-11 Desktop Color Primer
In this table, the shaded areas indicate that 200 ppi is typically the best trade-off
between image quality and file size. However, higher resolutions (e.g., 250 to 300 ppi)
may be needed for offset printing, when quality is of the utmost importance, or for
images containing sharp diagonal lines.
To find the best image resolution for your purposes, make test prints of some raster
artwork at different resolutions. Start with a high-resolution image (400 ppi) and save
versions at progressively lower resolutions, down to 100 ppi, using a pixel-editing
application such as Photoshop. Always save a copy of the original high-resolution
version in case you need to revert to it. The high-resolution data cannot be recreated
from a lower resolution version.
Print the files and examine the output. You will likely begin to see a marked
deterioration in output quality at resolutions below 200 ppi, while above 200 ppi the
improvement may be very subtle.
Image quality
100 ppi 200 ppi 300 ppi 400 ppi 500 ppi 600 ppi
Image resolution
Raster images prepared for offset printing may need to be at higher resolutions than
needed for proofing on your ColorPASS.