Thomas Forster worked in an unusual and demanding medium now largely forgotten: plumbago, meaning graphite or "lead pencil," applied to vellum with an exactness of touch that the early biographer Lionel Cust described as drawn "with exquisite care and feeling." Active in England between roughly 1695 and 1712, and recorded in the Oxford Dictionary of National Biography as born around 1676 or 1677, almost nothing else is known of his life, a common fate for specialist portrait draughtsmen of the period whose reputations rested entirely on the small, intimate objects they produced rather than on public exhibition or documented biography.
Forster's small portrait drawings, many clearly intended as the basis for engraved book frontispieces, depicted a genuine range of notable sitters, including King James II, the Speaker of the House of Commons Sir Thomas Littleton, the Bishop of St Asaph William Lloyd, and Archbishop Ussher, several of which were engraved for publication by Michael Vander Gucht and other printmakers of the day. Unlike contemporaries such as David Loggan and Robert White, who worked in a similar plumbago style but were themselves practising engravers, Forster appears to have confined himself to the original drawings, leaving the reproduction to specialists. A number of his works were included in a landmark exhibition of portrait miniatures at the South Kensington Museum in 1865, and examples are held today by the Ashmolean Museum, the Metropolitan Museum of Art and the National Gallery of Art, Washington, among others.
The work by Forster held by John Mitchell Fine Paintings, a portrait of an infant, exemplifies the delicate precision of plumbago portraiture at the turn of the eighteenth century, a specialist and now little-practised technique that Forster brought to a genuinely high level of accomplishment.