A full-length portrait to left seated at a table. He wears a captain's uniform (over three years), 1767-74, and a white wig and buckled shoes. His left hand is on his knee and his right rests on a chart on the table. Also on the table is a pair of dividers, a globe, a paper knife and a book. In the right background on the wall is a painting of a ship off the Cape of Good Hope.

Affleck spent his early sea training in the service of the Honourable East India Company before transferring to the Royal Navy. He became a lieutenant rather late in 1755. Boscawen made him a commander during the taking of Louisbourg in 1758 and, after following the admiral to the Mediterranean, he was made a captain after the Battle of Lagos in the following year. In the War of American Independence, he commanded the 'Triumph', 74 guns, and fought at Rodney's two actions with de Guichen in 1780. After getting his flag in 1787, he went as commander-in-chief to the West Indies, 1790-93. On his return he became a Lord of the Admiralty until he retired in 1796. By his death, in Bath on 21 December 1799, he had risen to Admiral of the White. It is likely Affleck was born in 1726, and he was certainly the younger brother of Edmund Affleck, also an admiral (1725-88), both being from a family of eighteen children. The Museum also has miniatures of both in their later years (MNT0049 and MNT0050) though these are rather damaged.

Penny was a pupil of Hudson and later travelled in Rome. He was the chief rival to Zoffany in the small full-length and was the first Professor of Painting at the Royal Academy from 1768 to 1782, when he retired through ill health.