MX-PEX1 (serv.man12). Fiery PEX1 Colour Reference Guide - Sharp Copying Equipment User Guide / Operation Manual. Page 88

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. 

Raster images prepared for offset printing may need to be at higher resolutions than necessary 
for proofing on your Color Server.

Ideally, each raster image should be saved at the actual size, and it will be placed in the 
document at the optimal resolution for the printer. If the image resolution is correct for the 
printer, there is no quality advantage to be gained by scaling an image to a percentage of its 
actual size. If you scale a large image to a percentage of its actual size, you incur unnecessary 
file transfer time, because the image data for the entire large image is sent to the printer. If an 
image is placed multiple times at markedly different sizes in a document, save a separate 
version of the image at the correct size for each placement.

If you must place an image at greater than 100% in a document, remember that the output 
image resolution is affected. For example, if you scale a 200 ppi image to 200%, the image is 
printed at 100 ppi.