Photoshop files (or all types) are fully tranferable between PCs and Macs, I do it all the time- just remember to add the extension .PSD on older Mac versions (I think 6 aand sometime 5.5 does it for you). The main differences, incidently, is the gamma, but newer Photoshops should ask you if they can convert, let it. Incidently, sort of a trivia question, but the difference between Mac and PC Tifs is PCs use LSB counting (least significant byte first) on numbers over 256, Macs (and most of the word) use MSB, but there is also a byte in the header that tells the App which one is used, so it really doesn't make any difference which one you set for a "proper" program. I'm sure you didn't want to know all that ;-) Oh yeah- do all your exchanging on PC disks, Macs can read 'em fine, as long as they have System 7.5 or better.