Shorefly - Placopsidella grandis Cresson
Collection of the Smithsonian Institution - 1982
Medium: Carbon dust on Cronaflex matte mylar
Size of the original is approximately 9x12 inches.

This illustration is actually two views of the same specimen. I found that this was an effective way to show more detail than what is commonly seen from a dorsal view.

Wayne N. Mathis - Studies of Psilopinae (Diptera: Ephydridae), I: A Revision of the Shore Fly Genus Placopsidella Kertész. Smithsonian Contributions to Zoology, No. 430, pg. iv, Smithsonian Institution Press, Washington, DC, 1982

The carbon dust technique used on this illustration may not be known to those of you who are unfamiliar with Scientific and Medical Illustration. It is essentially a refined charcoal drawing, in which fine dust ground from carbon pencils is applied to the work surface with a brush, chamois, or paper stump and the form of the specimen is developed. Then using the carbon pencils, detail is carefully worked in over the form. By using kneaded and other types of erasers, areas could be lightened, and highlight defined. For crisp detail, an xacto knife, needle or some other sharp instrument was used to scratch away the carbon to reveal the substrate. A method often referred to as scrafitto, and is the same method used on black scratchboard to create white lines.

Early medical illustrations were done on bristol board coated with a fine white clay that had a textured matte surface, but this media became more and more difficult to find. As a result, many of us began using various types of other media such as frosted or matte mylar films. The use of carbon dust allowed a skilled illustrator to create illustrations that had a photographic appearance, but the mylar films resulted in illustrations that had a soft appearance if not backpainted with white acrylic so that you could get bright white highlights. The clay coated papers were superior in this instance, as the clay itself was bright white and the carbon could be scratched away to reveal the clay.