Photo Printing and Resolution

Alpha Tutorial :29 - Photo Printing and Resolution

What is Resolution?

What is Resolution?

Digital image resolution – All digital photos are composed of tiny dots called “pixels”. In general, resolution is the expression of its size in terms of pixels. For any digital display, resolution is usually stated as it width by height in pixels. For example, a 1,920 × 1,080 photo means it is 1,920 pixels wide and 1,080 pixels tall. Resolution is used equally for photos as well as video.

Camera resolution – When shot by a camera, it and the resulting photo’s resolution is stated by its total number of pixels – which can be derived by multiplying the image’s width by height in pixels. Taking the last example, a 1,920 x 1,080 photo can also be expressed as 2,073,600 or 2.07 million pixels or 2.07 megapixels (MP). Manufacturers will always state a camera’s maximum resolution as its key specification. You can read more about camera sensor resolution here.

Print resolution – Besides shooting photos, editing and/or sharing them online, you might also want to print them out from time to time. Consumer A4-sized photo printers are very common and affordable today, but what you see on your screen may not correspond to actual print quality or size. That 1,920 x 1,080 (2MP) picture may look real good on your monitor or your Full HD widescreen TV, but a 2MP image is only good enough to print a 4R-sized photo.

Resolution in this sense doesn’t just refer to how many pixels the image that’s being printed is made up of, but also how many pixels can be printed onto an defined area – normally measured per inch. The denser the pixels can be packed, the sharper the image appears. This is normally defined as pixels per inch (PPI) or dots per inch (DPI).

So How Much Resolution Do You Really Need for Printing?

The quality of a printed photo is determined by three factors:

  • The photo’s resolution (in pixels)
  • The print resolution set on the printer (in PPI/DPI)
  • The actual size of the photo you want to print

Typically, home and commercial photo printers print at 300ppi. When you buy a magazine for example, it is printed at this resolution. This will be used as a baseline for our example.

The table below shows the ideal recommended image resolutions for each photo print size you wish to print. For each size, using photos of lower resolution than the ideal minimum image resolution will normally result in blurry or pixelated looking photos. Conversely, you can use photos of higher resolutions above the ideal resolution, but they will not make significant improvements to print quality as well.

Photo print size @300ppiIdeal minimum image resolutionIdeal minimum camera resolution
2.5 x 3.5 inches750 x 10500.79MP
3.5 x 5.0 inches1050 x 15001.5MP
4.0 x 6.0 inches (4R)1200 x 18002.2MP
5.0 x 7.0 inches (5R)1500 x 21003.2MP
.0 x 10.0 inches (8R)2400 x 30007.2MP
8.27 x 11.7 inches (A4)2481 x 35108.7MP
11.7 x 16.55 inches (A3)3510 x 496517MP

Modern digital cameras and even some mobile phones are capable of producing photos with a resolution of at least 12 megapixels, which is more than sufficient for printing a clear A4 photo that is the usual maximum size of consumer level home photo printers.

Although all digital cameras are able to have their resolutions selected, we recommend shooting on their maximum resolutions all the time as storage cards are extremely affordable these days, and so that you will be able to print any photo you have shot for any photo size without fear of insufficient resolution.

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