James Tarmy gets to the heart of the art market’s sublime (and infuriating) fixation on subtle details with his examination of the wide range of estimates on the same image by Alfred Stieglitz that will be auctioned in New York next week:

April’s coming New York photo auctions will feature a nearly unprecedented confluence of five Steerages up for sale: Copies of the work will be sold at Christie’s (April 6), Phillips (April 9), Sotheby’s (April 10), and Swann’s (April 19). Stranger still, each auction house has placed a different valuation on its image. At Christie’s, The Steerage is estimated to sell for $15,000 to $25,000; at Sotheby’s, $12,000 to $18,000; and at Phillips, the work is expected to fetch from $60,000 to $80,000. Swann Auction Galleries will sell two copies—one is estimated at $12,000 to $18,000, while the other, which is being offered with another Stieglitz image, is estimated at $5,000 to $7,000.

Each of the images was printed by Stieglitz from 1907 to 1916, and each (obviously) depicts the same thing. The price differential between the images boils down to minute differences in chronology, dimension, provenance, and signatures; in other words, it’s about connoisseurship and collectibility rather than artistry. “I think that photo collectors take these issues, which might seem like small differences, quite seriously,” says Christopher Mahoney, the senior international specialist for photographs at Phillips.