Unwanted pixilation on photos is often due to the usage of inappropriate image resolution in digital image processing. They are often referred to as ‘jaggy’ photos whether they are printed on a photo quality paper or viewed on a computer screen. High-res will mean the photo or graphic turns out crisp looking, while low-res photo resembles pixel art on video games.
Pixels Per Inch (PPI) and Dots Per Inch (DPI) are two terms that are often interchangeably used or misused by people to refer to the resolution of an image. While PPI is pixel density on screen, DPI refers to the dots on the printed photo. To draw an example, when people say they want a photo printed in 300 DPI what they actually mean is 300 PPI. That image resolution is often used for digital images to be printed on a paper – photo editing industry accepts it as ‘good quality’. On the other hand, 72 PPI is for photos meant to be used on the web.
Assume you have a photo with a resolution of 1697 x 1810 PPI, and you need that printed on an 8 x 10 inch glossy photo paper. For figuring out the maximum Pixels Per Inch, you can receive on the printout, divide the pixel width by the width measured in inches, do the and same for height. For instance, dividing 1697 by 8 inches will give you 212 PPI, and 1810 by 10 inches equals 181 PPI, which means the latter is the maximum image resolution you can get when printed on 10 inches size. Since 181 PPI is below 300 PPI, the digital version of the image will be pixelated and that will affect the printout even if you choose 8 x 10 inches photo quality paper.
To know the right dimensions that you can print the 1697 x 1810 PPI photo by maintaining quality, you may need to do some more math. Divide the width and height of the image resolution by 300 to find the maximum width and length on the printout. In the said resolution, you will get 5 x 6 inches, which means printing on that photo paper will give good quality digital images. In order to avoid jaggy photos, give pixel dimension of the photo a thought going forward.