Opalotype is an obsolete photographic printing process in which a carbon-based image is transferred onto translucent opal glass. The result is a delicate, luminous photograph with a soft, glowing quality that differs from traditional paper prints.
Opalotypes were popular in the late 19th and early 20th centuries for portraiture and fine art photography. While rarely used today, they are significant in the history of photography for their unique aesthetic and the innovative use of glass as a printing surface.