Most projectors are very low resolution - amazingly so, in fact. It is a very rare - and expensive - projector that shows 4mp (ie 2048x1536 - actually that's just 3mp). Most are more like 1.2mp. A surprising proportion are still 1024x768 or well under 1mp. Most of these resolutions are similar to what you get on the web!
What's even worse is that a fairly typical 1366x768 projector usually puts its million pixels on a pretty big screen area. It is very common to see that million pixels displayed on a 92" or 100" screen, meaning that the pixel density is a paltry 17 dpi.
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!