This was painted on a very thick, high-quality artists’ hardwood panel which (unusually) lacks a suppliers label on the reverse. Turner used the panel as a sketching board, and could have accidentally soaked off any label as he worked. He glued down heavy paper along all four edges, painted on the restrained paper (which could be soaked with water, brushed and scratched vigorously, and left to dry before repeating these processes, or even dried near a fire indoors), and later loosened it with a knife, then tore it off roughly.
The board was used several times. When it was upright, the paper was a half-sheet of the larger sheet that had previously almost filled the board. Traces of watercolour paint in many colours, blobs of animal glue, and knife and tear marks in the remaining paper, form the evidence for this alternative use. No other Turner sketching board has survived.
The panel may have been supplied with the slightly offwhite priming visible in many places. Initial thinned washes of coloured oil paint were strengthened with less-thinned paint applied with a broad, stiff brush that left its mark on the surface. More brush-strokes in the foreground than the background economically and rapidly created a sense of distance.
Clouds were applied over the bare priming with a broad, soft-haired brush and white paint: their warm yellowness is an effect of the paint medium. This was probably megilp, a gel-like material made from leaded linseed oil and mastic resin varnish, which could form both soft impasto and thin but continuous glossy paint films, and which was always yellow in tone. In thicker applications, the yellowness and the cracks that readily form as megilp dries can be obvious. Here it was used thinly, and over paint less rich in medium. This is the classically correct way to create durable paint surfaces – though Turner frequently broke this ‘rule’ and thereby promoted cracking and paint loss.