About: http://webisa.webdatacommons.org/205966436

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	A popular portrait method of photography from the 1839 announcement of its invention to about 1860, the Daguerreotype was a unique photograph with no negative???each photograph was exposed on a copper plate coated with silver-nitrate.
http://www.w3.org/ns/prov#wasQuotedFrom	si.edu