Image Resolution for Printing
Resolution must be assessed at the final physical size, not only by the pixel count or the DPI label stored in a file.
Effective resolution
An image loses effective resolution when enlarged. A small web image can look acceptable on a screen but become visibly soft when printed as a poster.
Viewing distance matters
Small print read at close range generally needs more detail than a large banner viewed from several metres away. Follow the product-specific minimum where one is stated.
Do not manufacture detail
Changing a low-resolution file from 72 DPI to 300 DPI without adding real image information does not restore missing detail.
