Realistic pictures created by a process of light passing through translucent panes of porcelain, it is a method invented and patented in 1827 by Baron Paul Charles de Bourgoing, and the attraction is that the light passing through creates a three-dimensional effect. Although developed in France, the process was perfected in Prussia. The Wadsworth Atheneum Museum in Hartford, Connecticut houses some of the lithophane collection of Samuel Colt, arms manufacturer, who used over 100 of them, purchased in Berlin, as window decorations in his Hartford mansion. Source: Herbert G. Houze, 'Samuel Colt's Porcelain Transparencies', "The Magazine Antiques", April 2006, pp. 106-115.