Another thing to keep in mind, although there isn't much that you can do about it is that as good as modern color films are, they don't neccessarily react in the same way as a human eye, especially with some dyes and pigments. It is possible to get the best, most accurate color rendition of a piece except that a certain Olive Green might go Brown or a Brown might come up Orange.
This is rarely a huge problem but there are some very finicky clients out there (especially artists). Kodak used to have a publication that photographers could hand out to clients who couldn't understand why every subtle color in a painting may not photograph exactly as seen.