Large portraits were expensive and only available to the wealthiest of patrons. D. A. Woodward was a portrait painter and thought that if a photograph could be enlarged but made week, he could then paint over the image, increasing the quality but also the speed of the portrait. In 1857 he invented The Woodward Solar Enlarging Camera which generated a weak but large image on canvas, developed in the sun that he then touched up and augmented with crayon among other medium. The combining of crayon and photograph gave birth to a new commercial portrait aesthetics in both photography and portraiture that enjoyed great success from roughly 1860 through about 1905, and in some isolated areas until the Great Depresion. These were the first "life-sized" photographic images that were available for portraiture. Artists used bromide, silver, and platinum prints as the photographic base. An out of print book (1882) by J. A. Barhydt describes the process of making the portraits, "Crayon Portraiture: Complete Instructions for Making Crayon Portraits on Crayon Paper and on Platinum, Silver, and Bromide Enlargements." Now and then a copy shows up on eBay for around twenty bucks or so. Unfortunately, the genre is not highly valued as a topic to historians of photography, as evidenced in most texts on the subject.

The crayon portrait was popular from 1860 to the early twentieth century. According to a State Historical Society of Missouri Newsletter, the process required to produce a crayon portrait started by enlarging a photograph onto drawing paper with a weak photographic emulsion producing a faint image. The artist then drew over the picture with charcoal or pastels, trying to duplicate the photograph while making it look hand drawn. The quality of the picture was entirely dependent on the artist’s skill. Tinting or gilding was sometimes added to enhance the effect. From a few feet away, it is often taken for a photograph but viewed up close, it can be seen to be a drawing.

Sources:
Aurora Missouri Historical Society
"Professor Woodward: Pioneer Photographic Inventor", Forays, 1996
"A Short Review of Crayon Enlargements: History, Technique, and Treatment", American Institute of Conservation, 1989
"Crayon Portraiture", by Jerome A. Barhydt 1890, a Project Gutenberg EBook

See also: Making the Positives: Crayon Portrait