There's a thread somewhere on here about it, but the most relevant stuff can be seen on this page

As someone who was there in Baltimore and saw it, I can say that the print was not pristine, but it was pretty darned amazing. There was definitely dirt on it, but not a whole lot. It was beautiful.

I'd say that the two things I learned about Star Wars at that showing were that the colors should be pretty vivid (although the photos of the screen overdo the contrast a bit), and it should definitely look like it was made in the 70s.