He executed his studies almost exclusively in pencil, even providing topographical information, yet the subtle atmospheric effects characteristic of Friedrich's mid-period paintings were rendered from memory.
Han udførte sine studier næsten udelukkende i blyant og medtog endog topografiske oplysninger, men den subtile atmosfære, som er karakteristisk for malerierne i Friedrichs mellemste periode, kom ud af hukommelsen.