The Surprise Judgments
Costamagna’s book is filled with examples of his judgment—corroborated by other experts, he assures us—elevating some artworks and demolishing the valuation of many more.

“Very often, people hate me,” he says. “But they respect me.”

There’s the example of his stumbling across a painting hanging in the Musée des Beaux-Arts in Nice and realizing it was Bronzino’s Christ on the Cross, “a work long since lost and vainly sought by connoisseurs of Florentine art of the period.”

In another instance, a group of Spanish collectors show him a painting. After examining it, he writes, “I looked up, and saw the shock spread across the faces of the three waiting figures as I announce, without preamble, “Gentlemen, this is a Bronzino.”

But all too often Costamagna says, art dealers who are desperate to believe that they’re in possession of a hidden masterpiece become angry, even belligerent, when he disabuses them of that fantasy.

“People always hope that they have a masterpiece,” he says. “Because masterpieces are more expensive.”

Just as often, he writes, dealers and collectors—willfully ignorant or otherwise— will ask him to authenticate an obvious forgery.

“Whenever I am confronted with a fake, I know it immediately,” he says. “One day, in a darkened room on the Faubourg Saint-Honoré, a foreign dealer-collector active in Paris asked me to authenticate, in front of two potential buyers, an obvious fake.”

Attribution, he continues, can be tricky. Forgeries are straightforward. “A fake always leaves an unpleasant impression,” he explains. “A feeling of discomfort.”

The Players
What makes Costamagna’s profession particularly interesting is that he seamlessly moves between the worlds of art dealers, art collectors, and art historians. If nothing else, his memoir is a passionate, if inadvertent, argument that the only thing that truly matters in the art world is expertise and genuine appreciation.