Christies NY is auctioning 50 Arbus photographs next week. Most appear to be printed after her death and signed by Doon Arbus. Should these command the high prices expected since they are not signed by Diane Arbus?
I think a print made by Diane Arbus sold for something like $500,000 a few years ago. So $20,000 to $30,000 estimate is probably reasonable for the later prints made by Neil Selkirk.
Well, whether you're into buying or not, you can still go check the prints out. The week or days before the auction Christies opens to the public to view the goods, or at least this is their usual protocol; info should be on their site.