Technique
According to his friend Richard Seddon, Nash almost always created his oil paintings in the studio, working from pencil or watercolour sketches he had prepared in the countryside.
In the studio, he sometimes worked at an easel with a mirror arranged nearby to give him a reverse view of his work. He mixed his oil colours on a plate-glass tabletop using linseed and poppy oils or petrol. His favourite colours were: Ash-Blue, Cobalt Green, Payne's Grey, Lemon Yellow, the Ochres, the Siennas, Terra-Verte and Crimson.

Wittenham Clumps 1943/44
Nash's colours were generally restrained until the last years of his life when he developed a more vibrant palette. Seddon remembers that this surprised even Nash himself.
For watercolours Nash used a box with ten whole-pan divisions, supplemented by watercolour tubes. The colours in the box included: Lemon Yellow, Yellow Ochre, Raw Sienna, Burnt Sienna, Crimson, Payne's Grey, Ash Blue, Lamp Black and Chinese White.
Seddon recalled that Nash never made a second attempt at a composition. If a watercolour did not work as intended, he would abandon it, saying that he had too many ideas in development for him to linger over any that did not succeed the first time.
The canvas of the Wittenham Clumps above is an unfinished work by Nash from the Tate's collection. Christie's, the British auction house, sold a similar unfinished view on paper in 2010.