1. Plural of heliotypy; a photomechanical printing process that uses the action of light on a sensitized surface to produce printing plates.
Usage: technical; printing and photography; largely historical; the process is rarely used in modern printing

Examples

• The museum's collection includes several heliotypies from the late 19th century.
• Early photographers experimented with heliotypies to reproduce their images in print.
• Heliotypies represented an important bridge between photography and traditional printing methods.
• The quality of heliotypies made them popular for fine art reproduction before modern offset printing.
• Collectors of vintage prints often seek out heliotypies for their historical and artistic value.