PSIG News: Resolution Information
October 12, 2004

You Say You Want a Resolution...

One question whice surfaces at almost every PSIG meeting is the question of resolution. There is an excellent resource from LTL Imagery which discusses image resolution in great detail. I believe it is one of the best explanations of the subject that I will not attempt to explain it further here.

Optimal resolution for desktop printers

As many photographers and hobbyists print from desktop printers, it becomes important to determine what resolution is best for each device. Instead of trying to cram large images through your printer, finding the optimal pixels per inch (ppi) will save you processing time and hard drive space. This will differ for all printers, but should generally be in the 200 - 300 ppi range.

To find the best resolution for your desktop printer, try this test. You will only have to do it once, and it is best to print full-pages at your printer's best setting to get an accurate result.

Obtain a full-page (8" x 10") clean 300 ppi test image; this can be a scan, stock photo, or digital image. Print this image at the full size and then change the image resolution in Photoshop under Image > Image Resolution; you will need to check the Resample Image option so that the resolution is lowered. Make prints of the same image at various resolution increments (275, 250, 225, 200, 150, 72 are recommended values.)

Compare the prints -- you will see that after a certain resolution, there is no discernable visual difference. This is the target optimal ppi for your printer. If it turns out to be 250, you can keep your images at 275 or 300 to be on the safe side, but going higher that that will not bring any more quality at that size.

Resolution reference chart

Additionally, provided here is a one-page informational PDF with resolution guide chart is available here (36 KB).