Technique and condition
This sketch was created on grey or grey-washed laid paper, using a fairly soft graphite pencil, freely and lightly for the figures and the background landscape that were drawn after heavier, probably ruled pencil lines which established the vertical lines of the arch. A warm brown wash, applied quite uniformly, economically depicts the arch, its shadow, the large tree on the right and the hillside beyond. This simple application of one colour instantly defined both the sky, and sunlit areas of foreground. Brownish black chalk and small, light applications of white gouache, and probably some washing out of the brown wash with clean water to create a whiter background for the gouache of the more distance temple-like monument, completed the sketch.
The sketch has in the past been covered with a window mount and over-exposed to light, which has faded the grey background colour of the paper until it is difficult to tell whether the paper itself was manufactured grey, or prepared with a grey wash. More noticeably, it has caused the paper to darken to brown. This has greatly reduced the contrast between the (unaltered) brown washed areas that define sunlit and shaded areas, and the reserves that defined ever larger areas of the composition. It has somewhat reduced the impact of the white gouache as well. The effect now is of a study in brown, rather than a deliberate contrast of greys, brown and white used to create a detailed sketch very rapidly.