Technique and condition
Turner has used the blue wove paper, which he often used in middle life, to great effect in this night-time composition. He painted a mixture of red vermilion and a black pigment over the blue paper to form the dark clouds and some of the water, and used thinner washes of black pigment to suggest the shadowy hill and middle ground. The spots of red pigment mixed with black for the clouds show up clearly in an X-radiograph of the paper, which indicates that the red is vermillion. The blue paper and dark washes surrounding it lend it a purplish tone that is an optical effect of the colours mixed with and around it, and which could wrongly suggest the use of a red lake with an unusual purplish tone instead. Lead white gouache highlights make the moon very bright in contrast to the evening light depicted. The moon also shows up clearly in the X-radiograph, indicating that it is painted in lead white gouache, as is its reflection and the brighter areas of the sky.
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. X-radiography also suggests that the yellow pigment is chrome yellow, which by this time had become Turner’s preferred yellow. It was available in an increasing range of shades, from pale yellow to orange, and finally scarlet by the end of his life. Here he used a mid-toned shade that seems to have been very newly available at this date. The blue pigment, rather little used because the blue paper could be utilised to give the effect of blueness, is probably ultramarine.