What dpi is necessary for ink-jet printing?

July 27, 2010 at 3:54 pm  •  Posted in Q&A by

I’m starting to make prints with an Epson 1400 ink-jet printer using images from my Nikon D5000. When sizing the image in Adobe Photoshop Elements 8, I set Resolution to 360 dpi as recommended by a friend who is a Photoshop expert. But recently I read an article that said I could use 240 dpi and another article that said to use 300 dpi. Who is right?
K. Melo

In this case, everyone is right. Most photographers use 300 dpi—actually ppi or pixels per inch—as the resolution when making ink-jet prints. However, for the absolutely best results, a 360 ppi setting is preferable. That’s because this is the ink-jet printer’s “native” resolution and produces the very finest possible outputs. In an 8.5 x 11” print you won’t see any difference at 360 ppi versus 300 dpi however, unless you use a magnifying glass.

The highly rated ink-jet photo printers (like the Stylus 1400) produce outstanding results from an image at 360 dpi and you may not see any difference if using an image with 300 ppi resolution.

When making much larger prints, the images produced by your camera are not adequately large for a 360 ppi setting. You can set 360 ppi for Resolution in the Image Size box when using Elements 8, but the software will need to enlarge the image file using interpolation (adding pixels). In that case, make sure that the Resample Image box is checked. The drop down menu beside the box should be at Bicubic (the best interpolation method in my experience.) Click on OK, and the file size will be increased as necessary for 360 ppi at the print dimensions you had specified.

Based on extensive testing, I find that most ink-jet printers provide very nice 13 x 19” prints even when resolution is as low as 240 ppi. That does require the printer’s own software to apply interpolation and this works well. Unless you are a perfectionist you would probably be satisfied with the results. Don’t use resolution lower than 240 ppi however, because you won’t be sending adequate information to the printer. Interpolation with computer software produces the best results so increase the image file size as necessary with Elements 8 to ensure that the resolution is at least 240 ppi before making a print.

A printer with a native resolution of 360 ppi will always interpolate if the image file was set to a lower resolution level, and this process works well unless the resolution is too low. High-grade software produces better results than the printer when using interpolation so it’s definitely worth resampling the image to ensure that it’s at 240 ppi or a higher level. © 2010 Peter K. Burian