One of the trickiest things to master when printing photographs is knowing the number of pixels to size your images by for a print. Since 4×6 prints are the most common, let’s talk about the right number of 4×6 pixels.
Pixels needed for 4×6 prints
In case you’re in a hurry, the correct number of pixels required for a standard 300DPI 4×6 print is 1200 x 1800 pixels.
Stick around for the longer explanation, which is really interesting and can help you calculate pixel size for pretty much any print.
The quality of your print is actually going to be determined by the DPI setting that your printer uses. DPI stands for Dots Per Inch.
This is essentially the amount of detail that your printer can reproduce in every square inch of your prints. Most standard photo prints are 300 dpi, so you need to multiply the inches you want to print by the DPI setting to get the optimal resolution.
300 DPI is an ideal setting for getting a good quality print. You can get away with 240 DPI too, but you don’t want to use anything less than that. Consider 240-300 DPI to be the standard for good photos.
Calculating image sizes for prints
For 4 x 6 print size, you need a resolution of (4 x 300) x (6 x 300) or 1200 x 1800.
For 5 x 7 print size, you need a resolution of (5 x 300) x (7 x 300) or 1500 x 2100.
For 8 x 8 print size, you need a resolution of (8 x 300) x (8 x 300) or 2400 x 2400.
For 8 x 10 print size, you need a resolution of (8 x 300) x (10 x 300) or 2400 x 3000.
You can very easily extrapolate the pixel dimensions for larger prints from these calculations.
Remember, 300 dots per inch is the magic number you want to try and maintain. It does not matter if you are printing at home or printing them professionally, try and stick to this number of the best photo quality.
Can you get away with smaller pixel dimensions?
Maybe, depending on the application you are looking for. I’ve managed to blow up 640 x 480 sized Whatsapp images that had a decently high dots per inch count into an 8 x 10 canvas print.
It printed fine on canvas because the textured appearance of canvas hid any potential graininess in the images from really popping out at you.
What about using extra pixels?
Suppose you have a really large digital image from your camera but you want to make a really small print. So instead of 1200 x 1800 resolution for your 4 x 6 print, you decide to double it to 2400 x 3600 and try a 4 x 6 print size.
At this point, you’re sending 600 DPI worth of data to the printer. Does this necessarily mean higher quality photos?
Not really, and here’s why.
First off, can the printer even manage to make use of all of that extra information?
Secondly, even if the printer pulled it off, can your eye really make out the detail without the help of an external tool like a magnifying glass?
Resolution on screen vs in print
Here’s where things get really interesting. If you own an HDTV, you’ll know that the resolution for full HD is 1980 x 1080 pixels. On a digital screen, 1980 x 1080 is considered very high quality and full of detail.
However, the 1980 x 1080 video resolution you see on a 50 inch screen is quite similar to the 1200 x 1800 resolution for 4 x 6 print!
One of the reasons for such a striking difference is the way in which you view screens vs the way you view photos. Screens are meant to be looked at from much further away(indeed, even computer screens) than photos, which you generally hold in your hand and observe very closely.
How to edit your photo for best results
Since the screen and print resolution is so different, here’s the best way to edit your photo before printing it.
- Resize your photo to match the pixel dimensions and pixels per inch that you need for your print
- Adjust the tone/color/brightness/contrast as you see fit
- Slightly sharpen the image since the resolution on screen vs the resolution in print will be much different. Don’t overdo the sharpening, though.