I have ALWAYS carried 2 or 3 extra <black & white> copies of my passport with me on int'l trips. I always leave my passport in the rental apartment or hotel, and carry a copy with me, and they have always been accepted if I have been asked for ID when using a credit card to buy something.

That said, for some reason, I just never thought of pushing the "color" button on my copier instead of the "b & w" button! I'll be sure to make color copies in the future!