The clouds and the vapours of real landscapes are not the same at the four seasons. In spring they are light and diffused, in summer rich and dense, in autumn scattered and thin, in winter dark and solitary. When such effects can be seen in pictures, the clouds and vapours have an air of life. The mist around the mountains is not the same at the four seasons. The mountains in spring are light and seductive as if smiling: the mountains in summer have a blue-green colour which seems to be spread over them; the mountains in autumn are bright and tidy as if freshly painted; the mountains in winter are sad and tranquil as if sleeping.^[3]

Guo Xi, Master Chinese Painter(c. 1020–c. 1090).