This image on white wove Whatman was the second copy of two images made by a copying process which Turner used to generate a limited number of copies from other lecture diagrams. The surviving original was a drawing of one column of the same dimensions (Tate D17061
; Turner Bequest CXCV 91), and the upper copy was used to illustrate realistic rendering of a rounded column, using a graded watercolour wash (Tate D17058
; Turner Bequest CXCV 88).
Turner 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 column look three-dimensional by shading, He could also use such a colonnade to form an entire elevation of the building. 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. 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’ side. 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; 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); two top copies now called Tracing of Guiding Lines
; CXCV 161) and Classical Columns
; CXCV 171) of a lost original and another copy Part of Classical Buildings, with Columns
; CXCV 170) of the same subject, and the set discussed here.
This sheet may have been the lowest one in the stack of paper, because the copying material can only been seen on the front, when this is examined in ultraviolet light, and the copied lines are faint. The middle sheet might be expected to show material on both sides, but in this case it does not (Tate D17058
; Turner Bequest CXCV 88).
Here, the copying process was used to make a single column with base and entablature. Then Turner draw graphite pencil construction lines for some perspective lines, and strengthened them in red, black and brown paint to illustrate the derivation of the vanishing point in considerable detail. The brown paint was made by mixing the red and black pigments, which are likely to have been vermilion and lamp black
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 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. 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
Joyce Townsend, 'Technique and Condition', March 2011, in Andrea Fredericksen, ‘Lecture Diagram 41: Perspective Construction of a Tuscan Column 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-41-perspective-construction-of-a-tuscan-r1136511, accessed 26 May 2019.