Silhouette methods - painted on glass

Once of the later techniques to emerge, artists have been painting silhouettes on glass since the end of the 18th century. As with other styles of painting, it has declined in popularity since the mid-19th century.

Typically, silhouettes were painted on the underside of flat or convex glass. They were then mounted on top of a backing, generally plaster or wax, with a gap left between silhouette and base. This allowed a shadow to be cast behind, enhancing the contrast and increasing the depth of the piece. One of the greatest difficulties of this technique is that the artist has to work in reverse. Silhouettists who worked on glass tended to be very accomplished artists.

Some painters on glass worked on top of a pre-painted background, rather than painting directly onto the glass. Isabella Beetham pioneered a technique called ‘fingerpainting’, where a solid black profile is painted over a base dabbed on with the fingers. The silhouette itself can be painted in watercolour or oil paint, often with the addition of gum Arabic for consistency. Silhouettes painted on glass do tend to have a greater level of detail, particularly regarding hair and clothing. Highlighting could be produced by simply scratching through the base with a fine needle. Early artists had difficulties with the consistency of paint mixes. This has been improved by modern innovations in paint production.

Important historic examples of painting on glass are the ‘Etruscan’ profiles of Jason Spornberg and the ‘anti-Etruscan’ work of Charles Rosenberg, both active in the 19th century. Spornberg’s ‘Etruscan’ portraits are distinctive for their vibrant profiles in vermillion enamel with scratched Etruscan style pattern borders. Rosenberg’s  ‘anti-Etruscan’  portraits were painted in black then backed in orange paper.

The Etruscan technique belongs firmly within the tradition of painting on glass. However, when employing this method the artist is effectively working in reverse; in the standard painted-on-glass technique the silhouette's profile is black but, in the Etruscan form, the artist paints primarily outside of the profile, leaving an empty space as the silhouette.

An integral part of an Etruscan silhouette consists in planning the border and finishing it and the portrait with vermilion paint, carefully brushed over the entire work.