Mike Boehm keeps the story of the Norsigian trove of negatives rolling along with the latest speculation that the images were shot by Earl Brooks, at least that’s what Adams’s former assistants, John Sexton among them, think. But final proof lies in comparing the Norsigian negatives to the known Adams negatives:

In an interview last week, Sexton told The Times that conclusive proof could well lie in the negatives themselves. Because all 44,000 Ansel Adams negatives are archived at the Center for Creative Photography at the University of Arizona, a physical comparison should be made between Norsigian’s negatives and identically sized glass negatives from the archive — with particular attention to clear spots along the negatives’ borders that invariably were caused by the wooden holders and metal clips used to slot the glass plates into old-time cameras.

Mark Osterman, an expert on photographic processes at the George Eastman International Museum of Photography in Rochester, N.Y., and Paul Messier, a Boston-based photographic conservator with high-profile expertise in photographic authentication, said last week that such proof could be telling if there were distinctive irregularities in the known Adams negatives that had been caused by the plate holders. Because photographers used their holders over and over, Norsigian’s negatives should then have the same unexposed clear spots as the known Adams negatives. Messier said other useful comparisons could be made by testing the chemical composition of the two sets of glass plates, and their emulsion residues.

Ansel Adams Garage-Sale Find Debunked? Experts Say Yosemite Shots Are By Earl Brooks (Los Angeles Times)