Blake used the medium of watercolour throughout his career. But while contemporaries like J.M.W. Turner (1775–1851) and Thomas Girtin (1775–1802) were using watercolour to evoke natural effects and convey a sense of spontaneous creativity, Blake thought of it as a form of fresco. His emphasis on the drawn line and bright, clear colours was intended to evoke the great wall paintings of Italian Renaissance painters. He also experimented with a form of tempera (a medium mixing pigment with water and glues). He similarly termed this fresco.
From 1799–1805 Blake executed a long series of Bible illustrations for his most reliable patron, Thomas Butts. He also produced many paintings of literary themes and invented subjects. Although his surviving pictures are small, Blake said he wanted such images to be painted on a large scale in public buildings. In 1809 he held a one-man exhibition and declared his ambitions in print, but almost no one came and he was dismissed as a madman.