Scott Reyburn raises an interesting question about Rodin whose work reached a peak of $20m last year even after much of the boom in sculpture of several years before had already passed. Nonetheless, the Rodin market has only recently begun to get the kind of structure and authority that other more valuable sculptors like Giacometti have.

“It was a game-changer when the Rodin Committee started issuing certificates,” said Edward Horswell, director of the Sladmore Gallery in London, a specialist in 19th-century French bronzes that has a set of five small lifetime casts of “Burghers of Calais” for sale, priced at $2.4 million. “That certainty gave a boost to prices at auction. Before then, it was only a few expert dealers and collectors who knew what they were buying. It was a real minefield.”

Mr. Horswell, like many Rodin specialists, divides the sculptor’s output into “lifetime,” “middle” (which the dealer puts at 1917 to 1952) and “late” periods. Lifetime casts are traditionally valued at three times the price of posthumous versions, he said.

So far the Rodin Committee has received 3000 queries. One of the problems with both Giacometti and Rodin is that there were a number of fakes created. Also, there was the issue of volume:
a former special adviser at the Rodin Museum, estimates the number of “legal” bronze casts of Rodin sculptures in existence at 8,000, with an additional 500 versions in marble, mainly carved by assistants. From 1898 to 1918, he said, no fewer than 316 bronze versions of “The Kiss” were cast, in four sizes, under license by the Barbedienne foundry.