Resolution - Print Size Chart The numbers on the chart stand for dots per inch (dpi) they say the human eye does not see much beyond 96 dpi, that should give you a good example of what will work to make a good quality print.
Pixel dimensions chart for high resolution digital photos
Trying to convert your digital image pixels into cold, hard, printable inches? Look no further. Here are the conversions we recommend for the following common photo sizes.
Printing images - what file size do you need? Resolution, pixel sizes and file sizes compared for print
A researcher has found that historical estimates of some of the largest ocean creatures are not correct.
pocket hole screw size guide
Pixel Size and Print or Web Use | Tutorial by Gretchen Willis - http://www.inbeautyandchaos.com/pixel-size-print-web-use-tutorial-gretchen-willis/
Lens aperture and diffraction. Nikon D5100 due pixel size 4.8 µm above f11 starts to show difraction, while Nikon D4 with pixel 7.3 µm shows difraction above f16.
Understanding Diffraction - Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks