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Prepared by Turner for his lectures as Professor of Perspective at the Royal Academy, Diagram 73+ is associated by Maurice Davies with a group of diagrams numbered 60–73, 75 and 76 (see Tate D17085–D17097, D17099, D17101) all dealing with the production of shadows. Although some of the diagrams are mentioned at various points in the manuscripts, many are not discussed at all, leading Davis to conclude that they may have been part of a lecture that is now lost, which ‘could have been given in 1811, possibly as part or all of lecture 4 or 5’.
There are indications that Turner used a sharp edge (perhaps the nib of a pen) to trace elements of the diagram and to add perspective lines in order to make another, now unknown diagram.
Peter Bower states that the sheet is Pott Quad size paper made by Joseph Ruse at Upper Tovil Mill, Maidstone, Kent.1 Elsewhere, Bower writes that the Ruse papers used for the diagrams are not very well made. ‘Indeed the majority of these generally large and heavy weight papers were probably sold as “outsides”. This drawing is on a cut-down sheet, originally made in a size of paper hardly ever found after this date: Pott Quad, nominally 32 x 25 in and most commonly made for printing, sometimes for writing, and never, as far as [Bower] can ascertain, for drawing. Given the way the colour has been worked on this particular surface [Bower] would judge this batch of Ruse Pott Quad had been made as a writing paper’.
Notes in Tate catalogue files.
See Tate D40010.
Supported by The Samuel H. Kress Foundation