 He moved to London in about 1789, where he worked for John Boydell, a major print publisher, and enrolled in the Royal Academy Schools.He made his first mezzotint in 1795, working from a portrait of John Kirby, the keeper of Newgate, painted by his friend John James Masquerier, and immediately afterwards produced a stipple engraving after a portrait of Joshua Reynolds.Turner's biographer, Alfred Whitman, dismisses a tradition in the artist's family that he was apprenticed to George Jones, who was in fact younger than Turner, but suggests that he may have come under the influence of George Jones' father John Jones, who was a notable exponent both of mezzotint and stipple, without making any mention of any formal apprenticeship.