Turner made many dozens of sketches
of the dramatic and sometimes hostile Alpine scenery during his 1802 tour of Switzerland. This view of a deep gorge, one side drenched in sunlight and the other plunged into darkness, was made on grey tinted paper.
The initial pencil work, visible underneath the layers of paint, is vigorous, almost violent. Vivid layers of gouache have been used to convey the density and wildness of the mountainous landscape. Turner
has created highlights by physically scratching through the pigment to
the white paper below.