The Collaborative International Dictionary
Heliotypy
Heliotypy \He"li*o*ty`py\, n. A method of transferring pictures from photographic negatives to hardened gelatin plates from which impressions are produced on paper as by lithography.
Wiktionary
heliotypy
n. A method of transferring pictures from photographic negatives to hardened gelatin plates from which impressions are produced on paper as by lithography.