John Thirtle (22 June 1777 – 30 September 1839) was an English watercolour artist. Born in Norwich, where he lived for most of his life, he was a leading member of the Norwich School of painters.
Much of Thirtle's life was undocumented. He was apprenticed to a London frame maker before returning home to Norwich. There he set up a frame-making business, whilst continuing to paint, as well as working as a drawing-master, a printseller and a looking glass maker. In 1812 he married Elizabeth Miles, the sister-in-law of the artist John Sell Cotman. He suffered from tuberculosis during the last two decades of his life, and his worsening health reduced his artistic output up to his death in 1839. He produced relatively few works; his unpublished manuscript Treatise on Watercolour was probably for his own use, and he exhibited fewer than 100 paintings. He was a member of the Norwich Society of Artists and briefly served as its vice-president, but in 1816 he was one of the artists who seceded from the Society to form a separate association, the Norfolk and Norwich Society of Artists, which dissolved after three years.
The majority of Thirtle's watercolours are of Norwich and the surrounding Norfolk countryside, many being riverside scenes. His style, influenced by Thomas Girtin, Crome and (to a lesser extent) John Sell Cotman, was technically accomplished. His earlier landscapes were painted with a restricted range of buffs, blues and grey-browns, but he later developed a brilliancy of colour, producing works that included angular block forms. The quality of several of his watercolours has deteriorated due to the fading of the Indigo pigment that he used extensively.
John Thirtle Old Lynndate not known