During a recent trip to an archive north of the Highland Line, I began to ponder the evolution of colour conventions. I watched the archivist unload cardboard boxes from the filing trolley, then untie the little cotton ribbons to release rolls of tracing linens and dyelines. The Victorian and Edwardian working drawings had brightly-coloured walls, roofs and founds which peeked out from the curve of the sheets.
Architectural drawings from the Italian Renaissance were usually monochrome, but I’ve read that the French military engineer Sébastien de Vauban was the first to introduce colour to his sectional drawings. Eighteenth century architects in France and the Low Counties appear to have adopted de Vauban’s idea of shading the cuts on cross sections with a pink wash. I assume the habit spread across Europe thanks to foreign architects who trained at l'École des Beaux-Arts in Paris then returned to their home countries.
From there, a set of conventions developed, and most Dean of Guild and contract drawings from the nineteenth and first half of the twentieth century use the same set of colours to denote materials. The best of them have ruled Indian ink lines and vivid washes of colour on stout cartridge paper that’s stayed white – rather than the dull, fugitive watercolours of the early 19th century on cheap paper which by and by has faded and foxed.
In the Georgian era, two centuries beforehand, the drawing began with pencil guidelines, then the architect drew over the pencil sketch using a ruling pen with india or bistre ink. Typically thinner lines or diluted ink were used to outline more distant forms; heavier darker lines outlined the structures in the foreground. Unlike today, human figures, dogs and cars weren’t added to anchor the architectural scale. Finally, the drawing was brushed with diluted washes of colour.
The consensus seems to be:
Yellow for wrot timber
Pale orange for unwrot timber
Brown for masonry
Red for brickwork
Dark blue for iron and steel
Turquoise or green for concrete
Bright orange for copper
Purple for insulation and also render or roughcast
Pale blue for glazing
So two hundred years ago, the architect and artist used exactly the same techniques and materials. You only have to look at the work of Francis Towne, the “Lone Star of Watercolour Painting” as Adrian Bury’s book called him, to see how he influenced the architectural perspectivists working even a century later, and their line and wash techniques were also used for orthogonal drawings.
Speaking to a recently-retired colleague, he recalls that colouring-up drawings for Warrant was an absolute requirement back in the day. It had to be done for all drawings whether new build or extension, although latterly the requirement was only to colour the extended area. Colouring started to fall by the wayside as printing methods changed. For example, architects used to make copies on linen sheets, but those were supplanted by plastic sheet copies, which he recalled were terrible things to crayon on …
I entered practice towards the end of the tradition, so only had a few years of sending Building Control “two papers and one plastic” (some older officers even referred to them as, “two papers and one linen”) before the Portal appeared and the chore of printing and folding then the Post Office run, was replaced by the chore of uploading PDF files. Even so, a few Building Standards departments such as Midlothian still request a drawing in what they refer to as "traditional" colours…
Until then, I coloured up a print occasionally, but it was usually with coloured pencil on a plain paper copy by that time – or maybe the last of the dyeline prints, during holiday jobs while I was still at architecture school. The death knell for hand colouring drawings would have been accelerated as CAD came more to the forefront and practices started invested in colour-capable printers which allowed the drawings to be more realistically rendered by computer.
Downtakings are still dotted red, which is a convention that survives – even though the multi-coloured sections and details haven’t lasted into the CAD era. But coloured pencil or CAD both compare unfavourably to the pleasurable but exacting task of using coloured wash. The archive drawings were originals drafted on heavyweight cartridge paper, and were effectively pen and ink manual copies of the original drawings made for tender, contract or record purposes.
Plan copiers were rare beasts at the turn of the 20th century, and while big city practices like Keppies had access to a heliostat or velograph machine at the time when Mackintosh was working on the Glasgow School of Art, it took several decades for diazo (dyeline) copying to emerge as a universal method. Until then, you worked on originals, and copies were manually made on tracing linen.
As my retired colleague noted, “I’m not sure at which stage junior staff would have been entrusted with colouring up and potentially ruining expensive, hand-drawn proposals. Pretty far down the line, I expect.” Running a wash and getting it badly wrong would be a game of jeopardy which the apprentice just couldn’t afford to get wrong. There’s no Ctrl-Z command in watercolour painting.
Meantime, a side effect of spending time in the archives was the need to buy an Imperial scale rule to measure the archive drawings with. All I’ve ever used is metric, whereas this is the realm of 1/12, 1/24, 1/48 and 1/96 scale. So off to Ebay we go…
Nevertheless, it could be worse. They said of the Vikings “Once you’ve paid the Danegeld, you’ll never get rid of the Dane” and CAD software firms learned that lesson at the start of the CAD era in the late 1980’s. Once you’ve bought CAD licences, you’re trapped – the software libraries and proprietary filetypes are embedded in ways that would be painful to unpick. So you have to keep stumping up licence fees. CAD software firms are the classic rentier capitalists.
I’d be very interested to read more about the evolution of colour conventions from years gone by: I searched books and hunted for research papers, but didn’t find much at all. Like the Giant Rat of Sumatra in the Sherlock Holmes books, the story will probably never be told. As Conan Doyle explained, it may even be a story for which the world is not yet prepared…
It’s also a demonstration of the tacit knowledge an older worker holds in his head that a younger colleague can access by picking his brains. From experience, some graduates thinks you can learn about most things online, with little need for guidance or mentoring. Here’s a small lesson in just how wrong-headed that notion is.
So please get in touch if you have anything to add, as it seems this tradition has more or less died out. That’s a pity, because colour makes drawings more legible, and can lift them from mere working drawings into architectural artwork.
