By Luciano Migliaccio
The word gemmaux refers to a technique developed by Crotti around 1925. Gemmaux consists of joining pieces of colored glass, at times overlapping, which are glued to each other. It is a framed, dense mosaic of glass, which permits the filtering through of daylight or any other artificial light placed within the frame. In 1937, at the Exposition des Maîtres Indépendants, at the Petit Palais, in Paris, Crotti organized a series of public projections with gemmaux and was so successful that he decided to perfect the technique, exhibiting the panels so as to be viewed with fluorescent lighting. Crotti then offered Picasso a transposition of one of his canvases, La Femme à la Chaise, to gemmaux. Picasso commissioned another similar work and other reproductions of this type were made of the works of Braque, Rouault, and Matisse. From 1945, assisted by technician Roger Malherbe, Crotti perfected the collage and illumination processes and organized exhibits and an atelier. Picasso and Braque accepted reproductions of their works with the new technique and the Paris subway system commissioned several gemmaux for the luxurious Roosevelt station. Cocteau also drew several cards, which were reproduced by Crotti in gemmaux. The Masp work was donated by its owners, the São Paulo firm “Cristais Prado” in 1948.

— Luciano Migliaccio, 1998

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