From a great article over at the WSJ titled "Asking the Artist for a Do-Over:"
In 1995 the Museum of Modern Art purchased the complete set of Cindy Sherman's 1977-80 untitled film stills, considered some of the most important photographs produced in the contemporary era. Nowhere on the accompanying labels or on its Web site does the museum acknowledge that these prints were run off at the time of the purchase from the old negatives, because many of the original black-and-whites had been processed carelessly, resulting in severe color shifts and fading. "When people bring in an early work that's technically all wrong -- it's turned silver or something -- we print out another one," said Janelle Reiring, director of Sherman's gallery, Metro Pictures.
Now, this is something I have often thought about when it comes to photography. What's the most a photo can last? If I were going to buy Gursky's 99 Cent for 3 million dollars, I'd sure as heck want to know that it could be passed on from generation to generation like a painting can. Might this be the reason for photography not selling anywhere near the prices of the top contemporary canvases?
It would make sense to me that some sort of foundation be created by the big art photographers or their galleries ensuring (by simply keeping a high res. digital file for printing) that another pristine copy could be exchanged for the old one, which would then be destroyed, retaining the value of the work. Such a guarantee might make auction (and thus, gallery) prices rise.