All of which is silly: two objects which are in every useful way (ie looking at them) are the same should be worth the same. And photography is almost as well zdapted to mass production as literature: imagine if authors expected to make a living selling only 10 numbered copies of each of their novels...
Selling authenticity sounds remarkably like homeopathy, where the water is supposed to remember the presence of the active ingredient that has been so thoroughly diluted that there may be one or zero individual molecules in the precious vial. Should we also up the value of a particular print if it has been looked at by someone famous?
You are just giving galleries yet another point on which to raise prices!
Seriousy, though, I'd use a slightly different basis for evaluating value and vintage.
Where the photographer has also made the print, I would charge top dollar; where he has actually overseen the printing in person
, I would rate as a step less valuable; where he simply handed the negative or file to a third party and then went out for lunch, I'd reduce the value to pretty much nothing more than a decent print from the erstwhile Athena
In my mind, one cannot separate photographer from printer. Where the single head performs both tasks, you get the real deal. If the photographer can't print, or is too lazy to do so or is simply producing commercial photography, then that's a different matter, where the print/image is being used in a specific way that is not much to do with any sense of being an art object, but a selling aid.
It's the same with old painters: their work existed for religious or social commerce/patronage, and wasn't born out of contemporary notions of the art value, and so having a studio full of assistants do the donkey work was cool, and absolutely essential if anything was ever going to get finished. In essence, factory art but without the title, as was once again fashionable for a while in the Studio 54 era.
I suppose that it further illustrates the value that an individual artist's painting has and which photographs sometimes have, but not always.
The idea that two things are of equal value because they look similar or even amost identical doesn't, for me, hold water. Simply put: if I had one of Vincent's paintings on my wall, I would think of him
, the sadness and elation of his life, and how he had sat before that very painting and thought his deep or shallow or deranged thoughts as he was making it. That would be a huge part of the emotional kick or value for me, but a replica means none of that, just a copy. Might as well hold a clutch of worthless counterfeit €500 notes in my hand. Or go to the Ferrari dealership with my little credit card, expecting a favourable outcome.