Frank Mason challenged the art restorers.

In my resent post Restoration? I mentioned Harold Speeds reaction to the inappropriate cleaning of a Velasquez portrait by the National Gallery London. It seems that well known artists have been fighting this trend to restore works of art for ages.
Goya, Jacques-Louis David, Eugène Delacroix , Edgar Degas, Pietro Annigoni and Frank Mason have all spoken out about unsuitable and careless restoration.
Frank Mason (1921–2009) campaign for more than half a century, challenging art restorations around the world, including at the Metropolitan Museum of Art in New York and, later, at the Vatican in Rome.
Mason first attended the Art Students League of New York when he was 16. Later he became an instructor at the league taking over Vincent Dumond’s class in 1951.
It was while studying with Dumond in 1947 that the two men visited the Metropolitan Museum to see the then recently restored Rembrandts, later Mason recalled. "I was shocked to recognise definite alterations to these familiar and beloved works,"
Throughout his time at the league Mason collaborated with Jacques Maroger investigating the techniques and mediums used by artists in the 16th and 17th centuries. Maroger had been the technical director of the Louvre Museum’s laboratory during the 1930's. These investigations alerted him to the nature of the injuries being inflicted on paintings in the hectic upheaval of postwar art restoration.
After many years of writing and complaining about the cleaning of the Rembrandt collection at the Metropolitan Museum of Art in New York Mason led a large group of artists and students from the Art Students League in a demonstration outside the museum. Mason said "We are here to protest the destruction of our national heritage. In the last 25 years paintings have been literally skinned through over-harsh methods of conservation. The result is damaged pictures that look piecemeal and no longer represent their period but rather seem to have been done in the modern method."
(1976).
Subsequently Alexander Eliot, a former arts editor of Time magazine, said that in the early 1950s the director of the Metropolitan Museum then, Francis Henry Taylor, had confessed to him: "Oh, we ruined the Rembrandts ourselves."

As well as teaching at the Art Students League Frank Mason also completed many prestigious commissions. One of the most important being eight large pictures depicting the life of St Antony of Padua for the 11th-century church of San Giovanni de Malta, in Venice.



Frank Mason "The First Temptation"
Scenes from the Life of Saint Anthony of Padua, 1195-1231
oil on canvas, 82 1/4" x 52 3/4" (1964)