Are there differences between sending PC or a MAC files?
If you are crossing platforms, (from MAC to PC or vice versa), remember the fonts do not transfer well. MAC and PC fonts are different. Even if the program you are using is compatible, the postscript fonts may not be. This can create a shift in the entire “look” of the piece. Also, special characters are at different key combinations, which can lead to complications in finding replacement fonts. You must be sure to send hard copy proofs in this situation, so any major changes can be discovered and corrected. If a font substitution is made, customer approval will be required.
