DPI. Dots per inch. That’s how many droplets of liquid squeeze into an inch of your printed paper. PPI. Pixels per inch. That’s how many points of light live on an inch of screen. Simple enough, right? But what the heck happens when you want to translate your 1-inch, 72DPI logo to a 27-inch iMac that runs at 2560×1440 pixels? How do you deal with that?
Sebastien Gabriel, a designer on Google Chrome, penned an excellent primer to walk you through this, and other bits of the incestuous, complicated relationship between DPI and PPI that will prove helpful to any designer in a digital space.
Eventually, the article evolves to become a broader discussion of a screen’s resolution vs its exact physical size, and how a designer approaches graphics that are as likely to live on an iPhone’s tiny but super-sharp Retina display as they are a giant, but low-resolution television screen.
There’s no one major takeaway from the piece, other than maybe what any graphic designer already knows: “Never give only one version of an asset; cover every DPI,” as Gabriel puts it. Instead there are lots of little helpful guidelines. Consider each medium a person might see your graphic on, and offer them the optimal resolution for that distinct presentation, rather than assuming that software will stretch or shrink things properly for you.