What is a heliotype?

73 rue Claude Bernard, Paris / via Google Maps

73, rue Claude-Bernard, Paris / via Google Maps

Heliotype E. Le Deley, Paris

Héliotypie E. Le Deley, Paris

The heliotype was invented by Ernest Edwards (1837-1903), who later outlined the process in his book, The Heliotype Process (Boston: James R. Osgood & Co, 1876). Though earlier begun by others, it was Edwards who perfected the process in about 1870.

The Merriam-Webster dictionary defines a heliotype as a “photomechanically produced plate for pictures or type made by exposing a gelatin film under a negative, hardening it with chrome alum, and printing directly from it.”

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