(b. 1737, Anstruther, Fife, d. 1798, Edinburgh)
Scottish painter and engraver. He was a pupil of Allan Ramsay from c. 1752; in 1755 he joined Ramsay in Rome, where he remained for over a year, studying under the patronage of Robert Alexander, an Edinburgh banker. On Ramsay's return to Britain, Martin worked for him in London until 1775, painting most of the drapery work during the early and middle 1760s.
He had his own studio by 1770, by which time he had also produced his first self-portrait (now in the National Gallery of Scotland). Martin painted over 300 portraits in his lifetime. One of the earliest independent ones is the 1767 one of Benjamin Franklin (now in the White House, Washington, DC). His most influential works depict Scottish Enlightenment figures like the chemist Joseph Black (1787, Scottish National Portrait Gallery) and the philosopher David Hume (1770, now in a private collection), and noblewomen such as the Honourable Barbara Gray (1787).
Martin exhibited at the Incorporated Society of Artists from 1765 to 1777 (being elected its treasurer, vice-president, and president between 1772 and 1777), at the Free Society of Artists in 1767 and at the Royal Academy in 1779 and 1790. As well as producing his own paintings, he copied them himself in highly-praised mezzotints, as well as producing engravings of landscapes.
In 1780 Martin returned to Edinburgh. In 1785 he was appointed principal painter to the prince of Wales in Scotland. Martin died in 1797 at his home in Edinburgh.