DPI vs PPI
If you're working with photos of any kind, you've probably heard both of these acronyms used somewhat interchangeably. But in reality, they're meant to describe photos in two completely different forms.
PPI (as illustrated on the left) stands for "pixels per inch." This refers to the resolution of a digital image as it appears on your screen. Pixels are small squares of varying hues that, arranged on a grid, make up your photos. They're so small, we don't register them as anything other than a smooth image. The larger your PPI, the higher resolution your image is.
DPI (as illustrated on the right) stands for "dots per inch." This refers to the printing process, not the digital file! It takes multiple "dots" of ink to form one pixel. Therefore, your DPI will generally be higher than your PPI.
In general, don't stress out about it too much - our digitization team scans using the highest DPI possible, and our print platforms will always let you know if the resolution is too low!