In this watercolour painting on off-white wove Whatman paper, graphite pencil drawing is visible in areas of thin paint application. Dense, even washes were then used. These have been darkened with black washes, but never mixed directly with black. This is an early example of Turner’s use of Mars orange, a fine-grained, synthetic earth pigment of a brighter colour than any of the natural earth pigments. He used it throughout his life, often as a light wash to intensify another colour. Here he has also used local areas of it to dramatic effect, for the water-hammer, the large ingots of metal under the hammer, and parts of the costumes, which are of course illuminated by the red-hot metal.
The ingots themselves are painted in this intensely coloured pigment over an area of reserved white paper, to create a brilliant contrast with the brown- and grey-washed paper everywhere else, painted with a limited number of brown earth pigments and possibly a brown madder. Deep blue washes in the shadows above the ingots further enhance their glow, through the use of opposed cool and warm colours. This may well be an early use of Prussian blue, for Turner. The channel of water run off from the water-wheel, and emerging in the right foreground as a water supply for quenching the metal, is painted into a reserved white area too, but with more neutrally-tinted washes, to create a more muted highlight that does not eclipse the glowing metal.
The white spray from the water-wheel was created by scratching into the paint with a thick pin, or quite possibly Turner’s sharpened thumb-nail, which he was reputed to use for the purpose, and whose right-handed scratches can be recognised in a number of oil paintings. The spray is accurately depicted descending in curved lines, and for this he would have had to turn the paper upside-down for some of the scratches, if he always used his right hand for the task. This is not as surprising as it sounds: most right-handed artists use that hand for everything, and Turner was also reported to be able to correct and improve engravers’ proofs when they were upside-down. (Left-handed artists are more likely to work with both hands, to transfer a brush or other tool to the hand nearest to the mark about be made, and to avoid reaching across themselves.)
How to cite
Helen Evans, 'Technique and Condition', October 2008, revised by Joyce Townsend, February 2011, in Andrew Wilton, ‘The Interior of a Cannon Foundry 1797–8 by Joseph Mallord William Turner’, catalogue entry, January 2013, in David Blayney Brown (ed.), J.M.W. Turner: Sketchbooks, Drawings and Watercolours, Tate Research Publication, November 2014, https://www.tate.org.uk/art/research-publications/jmw-turner/joseph-mallord-william-turner-the-interior-of-a-cannon-foundry-r1150272, accessed 14 August 2022.