Close your bodily eye, so that you may see your picture first with the spiritual eye. Then bring to the light of day that which you have seen in the darkness so that it may react upon others from the outside inwards. A picture must not be invented but felt. Observe the form exactly, both the smallest and the large and do not separate the small from the large, but rather the trivial from the important.

Quoted in The Romantic Imagination: Literature and Art in England and Germany (1996) by Fredrick Berwick and Jürgn Klein, and in "Culture: Caspar D. Friedrich and the Wasteland" by Gjermund E. Jansen in Bits of News (3 March 2005)