Megapixels vs. Print Size

You just bought the latest Canikon at 18 megapixels or at 24 megapixels. How big of a print can you do? Almost unlimited. How can that be unlimited? Won't your photos become just dots? Actually that depends on a few of things:

  1. Viewing Distance
  2. Printing Process and Print Resolution
  3. Upsizing Resolution

Please note the order. It's the most important!

  1. Viewing Distance: Under 3 feet or under 1 meter, you should print at 300ppi. For a viewing distance of more than 3 feet, such as a print to be hanged on a wall, you should use 200ppi. Billboards are printed at 72ppi!
  2. Printing Process and Printing Resolution: For commercial offset printing, images have to converted electronically or by the traditional litho film and halftone screens to a pattern of dots, with a resolution measured in lines per inch: LPI. Printing presses do not work in PPI pixels per inch, but in LPI.

    • Newsprint presses use 85-110 lpi
    • Standard offset presses use 133 lpi for consumer magazines...
    • Standard sheet fed offset presses use 150 lpi for trimmed sheets of paper
    • Fine quality presses use 175-200 lpi for art books...

    For offset printing, the standard image resolution is 266-300 ppi at 100% image size and the printing at 133-150 lpi provides a ppi/lpi ratio of 2:1. This allows for a bit of “wiggle room” if you have to make a small or last-minute increase in image size without scanning again. If you remove the safety margin, you can use a ppi/lpi ratio of as little as 1.55/1 without any image degradation. This will give from 130 ppi for newsprint to 270-300 ppi for art books.

  3. Upsizing Resolution: If you need even bigger prints, you can upsize your photo. Both Lightroom and Photoshop allow you to upsize. Companies like Alien Skin Software make software that will upsize your photos and do a fantastic job. They can be used in Lightroom or Photoshop as plug-ins.

Megapixels Pixel Resolution Print Size @300ppi Print size @200ppi Print size @150ppi
3 2048 x 1536 6.82" x 5.12" 10.24" x 7.68" 13.65" x 10.24"
4 2464 x 1632 8.21" x 5.44" 12.32" x 8.16" 16.42" x 10.88"
6 3008 x 2000 10.02" x 6.67" 15.04" x 10.00" 20.05" x 13.34"
8 3264 x 2448 10.88" x 8.16" 16.32" x 12.24" 21.76" x 16.32"
10 3872 x 2592 12.91" x 8.64" 19.36" x 12.96" 25.81" x 17.28"
12 4290 x 2800 14.30" x 9.34" 21.45" x 14.00" 28.60" x 18.67"
16 4920 x 3264 16.40" x 10.88" 24.60" x 16.32" 32.80" x 21.76"
18 5184 x 3456 17.28" x 11.52" 25.92" x 17.28" 34.56" x 23.04"
35mm film, scanned 5380 x 3620 17.93" x 12.06" 26.90" x 18.10" 35.87" x 24.13"
24 6048 x 4032 20.16" x 13.44" 30.24" x 20.16" 40.32" x 26.88"
  • Before printing in Lightroom, don't forget to set/change the resolution to be printed at.
  • Please note everything is in inches. DPI, PPI and LPI are all per inch.
  • To convert the print size from inches to centimeters, multiply the inches by 2.54 or 2,54 depending on your country.