Published in "La Photographie en Amerique" (Quatrieme Edition) by A. Liebert (Paris: B. Tignol, 1884)
Mark Osterman (Facebook, 15 June 2018)
Here is a cove studio background. The curve allows a gradient to have the lighted side of the face against the darker side of the background and the shadow side of the face against the lighted side of the background. I have only ever seen one of these and it was in the Tomishige studio in Kumamoto, Japan.
