Your answer is  : discrepancy

Look at these few lines-

Prices by vintage prints( those made by a photographer soon after he or she made the negative) so drastically ballooned in 1990s that one of these photographs might fetch a hundred times as much as a nonvintage print of the same image.

See the content in bold. It refers to the fact that vintage prints of an image would result in a drastic price difference as compared to a non-vintage print. This drastic difference in prices points to a discrepancy, which someone would misuse to make profit by peddling so called "vintage" prints(notice the use of quotes, to question the authenticity of such prints).

You could argue the case for ambiguity, citing that there is ambiguity as to whether a print is vintage or not, but then when you compare this ambiguity with the discrepancy I described earlier, you'll see that discrepancy does fit better.

Hope this helps.

Your answer is: discrepancy

Look at these few lines:

Prices for vintage prints  (those made by a photographer soon after he or she made the negative) so drastically ballooned in the 1990s that one of these photographs might fetch a hundred times as much as a non-vintage print of the same image.

See the content in bold. It refers to the fact that vintage prints of an image would result in a drastic price difference as compared to a non-vintage print. This drastic difference in prices points to a discrepancy, which someone would misuse to make profit by peddling so-called "vintage" prints  (notice the use of quotes to question the authenticity of such prints).

You could argue the case for ambiguity, suggesting that there is ambiguity as to whether a print is vintage or not, but then when you compare this ambiguity with the discrepancy I described earlier, you'll see that discrepancy does fit better.

Hope this helps.