I suspect many visitors to the show will have thought that the print made from a heliotype plate was an actual photographic print, and few will have understood that the heliotype plate was actually exposed in contact with an engraving. 
<Context ref.>French Daguerreotypes: A Photographic Object. [En línia]. [Consulta: 7 juny 2006]. Disponible a: <http://photography.about.com/library/weekly/aa090803c.htm>