Sandby’s watercolour techniques and working methods were extremely experimental. They are not always easy to define, but we do know that the basic components for making watercolour paints have changed little since the eighteenth century. Finely ground mineral or organic pigments must be mixed with a binding agent and a wetting agent. The artist then adds water to the paint mix to create a translucent wash that can be spread across a paper surface. Sandby liked to use isinglass (made from the bladders of fish) as a binding agent mixed with gin and honey water. You can still buy isinglass in art shops today, although gum arabic (made from the sap of the acacia tree) works just as well and would also have been available to Sandby.
Sandby made most of his paints himself and seems to have enjoyed the process. Until watercolour ‘cakes’ were invented by the Reeves brothers in 1781, there was no standard palette and artists’ techniques were highly personal. We know a lot about Sandby’s painting processes through his correspondence with Colonel Gravatt, a friend and amateur student. In a letter dated 9 October 1797, Sandby revealed an interesting discovery for making black wash grounds: ‘… a few weeks ago I had a French brick for breakfast, the crust was much burnt in the baking, and scraped off the black and ground it with gum water and it produced the most excellent black colour’. He also experimented with charring peas for a similar purpose! He would keep his paints in small pans or shells and the colours needed to be moistened each day to prevent them from drying out.
Although Sandby is frequently referred to as the ‘father of English watercolour’, it is important to remember that the term ‘watercolour’ was used in a very loose sense in the eighteenth century. Sandby would happily combine ink, graphite and chalks with watercolour in some of his artworks. He also used a type of paint called bodycolour. Like watercolour, it is made by binding pigments in a water-soluble gum, but with the addition of a white pigment to make it opaque. Sandby would often use bodycolour when producing paintings to be shown in exhibitions as he realised that the more strongly coloured works would have a better chance of competing with oil paintings hung in the same room.
To learn more about how Sandby composed his watercolour paintings and the types of pigments he used, click on the gallery above and ‘show caption’ for each slide
Paul Sandby, Roche Abbey, Yorkshire, c. 1770s
Watercolour over graphite, 300 x 588 mm
Royal Academy of Arts, London
Photo © Royal Academy of Arts/ Slingsby
Text written by Francesca Herrick
© Royal Academy of Arts, 2010