Twentieth-century art historical research has devoted little attention to the study of watercolour painting techniques and artists' materials. This is especially true of the period following Turner's death, when watercolour is said to have been in decline. Yet the period 1850 to 1880 was a period of intense innovation and experimentation, when watercolour painting finally came to be accepted on an equal footing with its rival, the medium of oil. The expansion of annual exhibitions brought dazzling, highly finished works to the attention of the new middle-class buying public, who eagerly scanned the latest press reviews for news and guidance. For the first time, I combine unpublished material from sources including nineteenthcentury colourmen's archives, conservation records and artists' descendants' collections, with an analysis of contemporary watercolour manuals and art critical writing in the press, to give a picture of the dramatic changes in technique which occurred at this time. Brilliant new pigments and improved artists' papers and brushes flooded onto the market via a growing network of artists' colourmen. Affordable instruction manuals, aimed at the swelling ranks of amateur artists, were published, their successive editions highlighting the changing character of watercolour practice, in particular the growing use of bodycolour, microscopic detail and new tube pigments. Progressive artists such as John Frederick Lewis, Samuel Palmer, Myles Birket Foster, John William North and Edward Burne-Jones, developed revolutionary ways of incorporating the new artists' materials into their watercolours, often to great commercial success. Exhibition reviews by critics in the growing number of journals often commented loudly on the bright colouring, minute detail, texture and opaque effects produced by their use of the latest pigments, papers and brushes. The impact made on watercolour painting by improved artists' materials was farreaching, bringing power and status to a medium which had previously been considered an inferior artform.