This lecture diagram on white wove Whatman paper shows four identical columns topped by an entablature, and the cast shadow of another part of the building. The basic structure consists of the four columns, the entablature and the blocks of the wall behind the colonnade marked in behind three of the columns: this composition is an upper copy of a lost original, as is Tracing of Guiding Lines
; Turner Bequest CXCV 161). Another copy from a similar original is Part of Classical Buildings, with Columns
; Turner Bequest CXCV 170).
Each column has been competed differently in brown and grey watercolour washes, to give an unrealistic view, while illustrating possible ways of depicting depth in an image of a building. The colouring implies that the two middle columns lie further back than the outer two. On the left side, this was achieved by using a graded wash on the leftmost column to illustrate its roundedness while leaving its more distant neighbour evenly coloured and less distinctive, and applying the deep shadow over both. On the right side, the nearer column has vertical fluting and the more distant one is plain (or indistinct) and must lie further back, since the shadow does not cut across it. In fact a pale grey shadow painted on at the correct angle implies shading from a more distant portion of the building. All these techniques depend on the artist’s ability to apply accurately an even wash with a hard edge (achievable with fairly dry paper) as well as a graded wash with no sharp transitions, which would be applied to wetter paper, without using so much water that the edge smeared out as it dried. The yellow/brown washes round the detailed structure show how less-controlled washes would be ineffective to depict depth, though even here Turner has – apparently effortlessly – indicated the cast shadow in the leftmost portion with a darker wash.
This work was made by a copying process which Turner used to generate a limited number of copies from other lecture diagrams. It is rare that all or even most stages of the process survive, and there is no complete set in the Turner Bequest, since these materials were presumably transported to and used for a number of lectures over the years. He needed several copies so that he could if he chose illustrate the drawing of a single element such as a column alone, then later with perspectival lines going to a single point, or built up to a colonnade of identical columns, or used to illustrate the way to make a smooth column look three-dimensional by shading. He could also use such a colonnade to form part of the elevation of a building, as in this example.
The process seems to have involved placing a blank sheet on a table, overlaying double-sided copying paper, followed by another blank sheet, another sheet of double-sided copying paper, and the image to be copied. In this case it would have been either a single column or a four-column colonnade, drawn in outline. Then he pressed down hard on each ruled line of the top copy with a sharp tool run against a ruler, and unpacked the paper stack to reveal one good and one pale copy, with little smudging on the ‘good’ sides. If necessary, he strengthened straight lines in the copies, which would both be identical and not reversed, and then he hand-applied the curved elements freehand as necessary and/or painted the lines to make them bold enough to demonstrate to a large audience in a room lit artificially. Sets of copies identified thus far include: Building in Perspective
; Turner Bequest CXCV 81) which is an upper copy of a lost original and A House in Perspective, Lecture Diagram 36
; CXCV 82), and Building
; CXCV 83) which are both lower copies of comparable originals; the original Column
; CXCV 91) which was used to make Tuscan Column in Perspective, Lecture Diagram 40
; CXCV 88) as the upper copy and Perspective Construction of a Tuscan Column, Lecture Diagram 41
; CXCV 90) as the lower copy; Tracing of Guiding Lines of Diagram of Capital, Tuscan Entablature Worked Out in Perspective
; CXCV 107) which was used as the original for the copies Capital, Tuscan Entablature Worked Out in Perspective
; CXCV 106) and Tuscan entablature
; CXCV 109); and the group discussed here.
This example could have been generated from a drawing of a single column, or more likely a drawing of four columns, which has not survived. The image is slightly skew on the paper because the sheet was not lined up properly beneath the top copy. It provided excellent clues to the materials used in the copying process. On the reverse are traces of lamp black, clay-like silicate extenders (both identified by optical microscopy) and protein, which organic analysis suggests is either whole egg or egg yolk. In places they have seeped through to the front. This identification was made with a technique called Fourier transform infrared microscopy, which is done by comparing the results from known materials, and it is consistent with the appearance of these areas in ultraviolet light.
Recipes exist for home-made copying paper, and evidence from three groups of the lecture diagrams – smudges of black material, occasional smears and the incised lines – suggests that a mixture of egg yolk or whole egg with cheap lamp black was generally involved. Thin paper dipped in such a watery solution, left to dry, and used once, would have worked. The copying papers were not used repeatedly, since all the copied lines are crisp and even, therefore clearly made from virgin copying paper that was so cheap it could be discarded after one use. This process could have been done at home, and repeated on a top copy if more copies were required. There is precedent for using eggs too: a fair proportion of the primed canvases Turner used while his father was alive and assisting him in the studio carry a priming made from lead white and whole eggs. Possibly Turner’s father assisted with the copying as well.
Soap, butter or linseed oil to mix with dry pigments in a variety of colours were also recommended in household encyclopaedias for copying paper: vermilion for red, carmine for reddish pink, blue bice for blue. The organic analysis technique used here would be able to distinguish soap, butter and linseed oil form the egg detected here. Some instructions suggested that dry pigment strewn over the back of the top copy, or soft graphite pencil shaded on, could work for generating a single copy. Turner’s lecture diagrams look too tidy and clean on the reverse side for these last methods to have been used, and the making of successive copies off one top copy would surely have led to smudging on the front as well.
How to cite
Julia Jönsson, 'Technique and Condition', January 2007, revised by Joyce Townsend, March 2011, in Andrea Fredericksen, ‘Lecture Diagram 8/3: Elevation of a Stoa or Portico (after James Stuart) c.1810 by Joseph Mallord William Turner’, catalogue entry, June 2004, revised by David Blayney Brown, January 2012, in David Blayney Brown (ed.), J.M.W. Turner: Sketchbooks, Drawings and Watercolours, Tate Research Publication, December 2012, https://www.tate.org.uk/art/research-publications/jmw-turner/joseph-mallord-william-turner-lecture-diagram-83-elevation-of-a-stoa-or-portico-after-r1136469, accessed 22 January 2021.