DPI vs PPI What's the difference?

DPI vs PPI. These are perhaps the most widely mis-used terms in large format printing. They are routinely interchanged when in actuality they are two very different terms. To be sure, we all may have bigger issues than what term should be used here however if you're in to this sort of thing as I suppose I am, read on.

DPI or dots per inch is a unit used to measure the resolution of an output device, that is how many tiny dots of ink are being dropped in a one inch square. But here’s the tricky part, it’s not actually 100 dots per inch.100 dpi would be 100x100 per inch so the printer would actually be dropping 10,000 micro drops of ink in one square inch and it increases exponentially. 200dpi=40,000 dots and so on. 

PPI or pixels per inch is simply the number of pixels per inch in the digital file used to produce the output. The higher the better...but only to a point!

in the next issue... How much is too much?