Technique and condition
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 (Tate D17051; Turner Bequest CXCV 81) which is an upper copy of a lost original and A House in Perspective, Lecture Diagram 36 (D17052; CXCV 82), and Building (D17053; CXCV 83) which are both lower copies of comparable originals; Tracing of Guiding Lines of Diagram of Capital, Tuscan Entablature Worked Out in Perspective (D17077; CXCV 107) which was used as the original for the copies Capital, Tuscan Entablature Worked Out in Perspective (D17076; CXCV 106) and Tuscan Entablature (D17079; CXCV 109); two top copies now called Tracing of Guiding Lines (D17132; CXCV 161) and Classical Columns (D17142; CXCV 171) of a lost original and another copy Part of Classical Buildings, with Columns (D17141; CXCV 170) of the same subject, and the set discussed here.