Basic guide to print resolutions
Guide to getting high quality prints using the correct resolutions
If you want to print out digital photos its important to use a high enough resolution photo for the size you want to print and that is an important factor to think about when buying a new digital camera / phone / tablet. This print resolution tutorial will hopefully help you. I have based the guide around megapixels, there are other ways, but wanted to try to do all my tutorials the same way to reduce confusion.
Why worry about print resolutions?
The tables below are based on printing at 300dpi as that is pretty standard for a high quality printing, you can print at lower resolutions and still get good results, but if it's too low then it will turn out blocky or blurred if you look at it up close. If you want to show off you photos by printing them then printing them too big for the amount of data in the digital photo would not show the photos at their best, which would be sad if it was a digital photo you were very proud of. My guide only goes up to 20" x 20" as over that most prints would probably not be looked at as closely as to would a 6" x 4" print, so using a lower resolution / lower megapixel file would be fine.
How to work out the resolution you need
Use these tables, one is in centimetres, the other in inches, to work out either what you can print from you current digital camera or camera phone or if you are looking at buying a new one, but not sure if it will be good enough then hopefully this will help! Say you are looking a a very basic phone or tablet then some still come with 3mp (megapixel) cameras, this guide shows that it's photos will be fine for 6" x 4" photos, but too low quality for good results at 8" x 6". If the size you require needs a 6mp photo, but your camera is 3mp, then it will not come out well, but if your camera is 12mp it won't look any better than a 6mp one at that size, although you never know when you might want to print bigger, so go for more megapixels if you can, as bigger is better! ;)
300dpi print quality in centimetres
300dpi print quality in Inches
Cropping photos to increase zoom
It's also important to think about cropping digital photos, its amazing how much difference you can make to photos by trimming them down a bit, but when you do that you lower the resolution. Cutting an image down lets you focus on just one thing in the digital photo and is also a slightly sneaky way of increasing the zoom of your camera, so if you only want to print high quality photos at 6 inches x 4 inches then you could get a 9 megapixel camera with a 10 times zoom and then crop the image to half the size, it would have the same effect as using a 20 times zoom and the print quality would still be perfect. Due to things like that its always best to go for a higher megapixel camera that you actually need if you can afford to.
Printing different shape digital photos
No, I don't mean circle or star shapes! Virtually all digital cameras create rectangular photos, normally 4:3 (designed for 6" x 4.5", 8" x 6" etc.) or 3:2 (designed for 6" x 4", 9" x 6" etc.) If you need a different type of rectangle, for example if you wanted to print the middle 2" high strip of a digital photo 10" across, then if you want the best quality you need the original file to be the right quality for 10" x 8", not 10" x 2"! Confusing I know!!!
This guide was 100% created by Dean Thorpe of Death Prone Images, so please feel free to link to it if you think it is useful, but PLEASE do not copy it and use it on your own site, it took a lot of work to create. If you want to print it out for educational reasons then that is fine, just don't claim you created it or make profit out of it. Sorry to sound negative, but I have had a few bad experiences with people selling my creations on eBay!