Nuclear explosions, like this U.S. military test in the Marshall Islands in 1946, released isotopes into the environment, permeating the soil and ending up in natural oils used to make paint. (Associated Press)

A Russian curator says she's developed a foolproof method of determining whether a piece of art was made before or after 1945 as a way of sniffing out fake paintings.

Elena Basner told The Art Newspaper that she has developed a method in collaboration with Russian scientists based on the idea that man-made nuclear explosions from the 1940s to 1960s released isotopes into the environment.

These isotopes, Caesium-137 and Strontium-90, permeated the earth's soil and plant life and ended up in works of art made in the post-war era because natural oils, usually flax/linseed, were used as binding agents for paints.

"I wanted to find something ironclad … that couldn't be disputed, and this led me to approach scientists for ideas," said Basner.

More than 500 nuclear explosions since 1945

Basner, who now works as a consultant, says she developed the testing technique while working as curator of 20th-century art at the Russian Museum from 1978 to 2003.

"The number of avant-garde fakes out there today is unbelievable, probably more than the number of genuine works," says Basner.

She says she needed to authenticate Russian works dating from 1900 to 1930 and that's what led her and the scientists to examine the nuclear isotope idea.

The first nuclear explosion took place in July 1945 in the U.S. and from then until 1963 more than 500 were carried out by various countries.

Flax fields absorbed the isotopes from nuclear fallout, resulting in traces of the isotopes in natural oils used in paints.

At the very least works known to have been produced prior to 1945 can be authenticated because they won't have any traces of the two isotopes.