Click on the image to go to an article from The Tate website. It mentions Turner’s interest in Geothe’s colour theories.
“Turner relished the Sublime effects of darkness. Its mysterious and elusive charm could stir the emotions in passionate and disquieting ways, for example in his night-time scenes of Venice. While for Newton and Goethe darkness was merely a negation of light, Turner expressed it positively in his works using colour. Intense, matt pigments applied to paper with a reddish ground could be dramatically offset by touches of bright white.”