This unattributed photograph was an example of a photogravure plate produced by students at a private school of photography in Schloss Grönenbach, Bavaria. (Castle Grönenbach in Bavaria-now Bad Grönenbach)

From Eder’s History of Photography, this school established by Wilhelm Cronenberg is discussed:

“Another private school was established by W. Cronenberg, in 1858, at Schloss Grönenbach, Bavaria. This was a boarding school where instruction was given in the different branches of photography and later in the technique of reproduction. This school was very successful, and it did not close until 1900.  Cronenberg then moved to Munich, where he started a reproduction establishment; he died there soon afterward. He wrote numerous articles for the Jahrbuch and an excellent handbook entitled, Praxis der amerikanischen Photogravure (1899), which was translated into French by G. Fery.” 1.

1.  Josef Maria Eder: History of Photography: Translated by Edward Epstean: Columbia University Press: New York: 1945: p. 685