Do You Know Gemmaux?


Emily Ketterer


Newsletter, Gemmaux
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In 1953, the Chor-Bishop Mansour of a Brooklyn Heights church had heard whispers of a new French stained glass called gemmaux. Excited by the prospect of presiding over the first church to have all of its windows done in this style, Chor-Bishop Mansour Stephens of Our Lady of Lebanon promptly commissioned 10 windows from the artist that developed the technique, Jean Crotti.1

Years before the technique ever graced full-scale windows, it was first limited to small works. Swiss-born, France-trained Crotti would layer and adhere colored glass pieces onto a transparent panel and put them on view in front of a light box. The artist collaborated with Roger Malherbe-Navarre, a physicist and lighting expert, to help him perfect these adhesives and light boxes. Crotti sought a permanent adhesive that would fuse the glass together, but would also be completely transparent and not obstruct the light.2

Once he was satisfied, he patented this technique. His first patent was approved in 1933, with others filed in 1937, 1940, and 1951. The 1951 patent states that,  “The transparent and colored fragmentary elements are arranged in superimposed layers on the whole or on one or on certain parts of the transparent support in such a way that they can represent subjects placed in different planes, the most distant subjects being visible per transparency in through the others.”3

Essentially, colored glass pieces were cut and adhered to each other using enamel glues. Then the panels were immersed in an enamel solution and put into ovens to fuse.  Once they had cooled, the panels were typically mounted inside metal light boxes and lit with florescent lamps.4 One illustration from the 1951 patent shows different methods used by gemmistes to layer the colored glass.  Some examples show the glued pieces sandwiched between two clear pieces of glass, but in others the glass is simply glued on top of one transparent sheet. Each of these layers would have been attached to each other via a layer of Crotti’s clear enamel.

In 1954, the artist-inventor began copying Pablo Picasso’s paintings using his newly patented stained glass technique. When Picasso saw these creations, he announced, “A new art is born.” Other artists began to adopt the technique and the method was used commercially in Parisian subways. Crotti would pass away just a few years later in 1958, leaving Roger Malherbe-Navarre to continue his work.5

But today, Crotti’s pieces are extremely rare in situ. This is partially because some of his works began to fail several years after his death, including the windows at Our Lady of Lebanon. This failure could be seen in pieces falling from their original location and enamel layers separating from their glass base. The worst panels were replaced in the same method by the Lebanese artist, Saliba Douaihy. But the next time you find yourself in Brooklyn Heights, make a trip to Our Lady of Lebanon and catch a glimpse of a little-known, 20th-century stained glass method.

About the Author

Emily Ketterer is a Masters candidate in Historic Preservation at Pratt Institute. 



[1] Vahdat, Salma. "Stained Glass: Our Lady of Lebanon." In-person interview by author.

February 20, 2017.

[2]"Corning Museum of Glass." All About Glass | Corning Museum of Glass. Accessed February 22, 2017.

[3] Crotti, Jean. A method for producing multicolor effects analogous to those of stained-glass windows and products thereof. US Patent FR55000, filed September 11, 1946, and issued June 5, 1951.

[4] "Corning Museum of Glass." All About Glass | Corning Museum of Glass. Accessed February 22, 2017.

[5] "Corning Museum of Glass." All About Glass | Corning Museum of Glass. Accessed February 22, 2017.