When doing make-up for print work, what distinguishes it from other make-up techniques. I know titanium dioxide and other sunscreans are typicall avoided because they bounce the flash a bit, but other than that, what techniques really differ?

GENERALLY SPEAKING:

Print/Commercial MU is lighter than Stage/Theater MU.  They use different brands as well (Ben Nye, Mehron...).

Most MUAs wish to maintain a very "natural" look to the Print/Commercial models. They use lighter easily blended cosmetics (MAC, Lancolm, Bobbie Brown...) 

Stage/Theater MU is heavy, thick - like plaster (no, not like plaster - more like ten layers of extra skin).

Print/Commercial work brings the subject very close to the discriminating eye, so the MU needs to be hardly noticible (unless one is doing avante garde).   

Stage/Theater/Showgirl MU needs to be heavy and more gaudy so that one can see it from a distance...

Then there are prosthetics...

Technique used is really sort of dependent o what the photographer and art director feel is appropriate. 

Fashion models usually have light MU - Glamour models have thick MU.

Anything in particular you wanted to know?

Hmmm.. nothing pops out.  This goes back to a squabble I had with someone in which I basically stated that fashion and glamour make-up were not terribly difficult. He maintained that if I couldn't see the difference, it was only because I didn't know what to look for, but he couldn't tell me what to look for.

I actually started learning make-up for stage work and received some training a la drag queen ("Every contour has a shadow! Every shadow has a contour! Say it back or I'll beat you with this wire hanger!"). I'm working my way back to the natural look.