Technique and condition
This composition is on blue wove paper, visible in small patches at the lower edges where it functions as a pale blue. The deeper blue sky was painted with a transparent wash of ultramarine. In the rest of the painting several layers of coloured gouache have been used, followed by thin washes of watercolour. The buildings are painted in white gouache with grey detailing. X-radiography of the sheet indicates that the gouache was made from lead white. Turner was an early user of lead white in gouache, and by the middle of the nineteenth century other artists were also using it regularly. Lead white in scanty amounts of gum water as Turner used it, can easily discolour to a speckled or solid dark brown when it reacts with hydrogen sulphide gas, a common urban pollutant during the nineteenth century. Here, the gouache is in excellent condition.