![]() ![]() Later, artificial lights allowed the process to take place indoors. This contraption was then taken from the darkened room out into the sunlight and after about 15 to 30 minutes, the copy emerged: where drawing marks were, the paper remained the same, thus white lines on a blue background. When the process was first introduced, to copy an architectural drawing, the transparent original was laid onto the prepared blank sheet and together clipped into a wooden frame. The soluble chemicals are washed out in water. Areas of the compound exposed to strong light are converted to insoluble blue ferric ferrocyanide (Prussian blue). A compound solution of ferric (iron) ammonium citrate and potassium ferricyanide (salt) is coated onto one side of the paper that will be the copy. Blueprints are more correctly called cyanotypes (cyan = dark blue). Both blueprint and diazotype are light-based reproduction methods, photographic processes (photo = light graph = write), reliant upon the support being treated with a chemically-coated photosensitive solution but each is a result of different chemical reactions. And here, again, confusion and error in identification have crept in, with diazotypes often mislabelled as blueprints. ![]() DMC 2272.5.1.īut from about 1900 the blueprint was overtaken gradually by the diazotype print as the more standard copying process. Jean-Charles Moreux (1889–1956), perspective of an interior, Design for a block of flats, Rue Gazan, Paris, c.1927. Blueprint processes were amongst the first of these novel copying developments and became a common method for architectural offices to reproduce their drawings until the 1950s. Beginning in the middle of the century, mechanical printing methods escalated and revolutionised architectural practice copying architectural drawings became faster and the copied image more legible. Hand copy production was hastened by the rise of translucent supports, particularly tracing paper, which progressed through the nineteenth century from oil-soaked paper to industrially manufactured transparent papers. The more common procedure was scaling off, using drawing instruments such as rule, divider and compass, transferring measurements from original to copy. ![]() The less common practice was pricking: the original drawing was laid over a blank sheet and punctured at key points with a metal needle-pointed pricker the copy below was then finished by joining these perforations together in pencil or ink. Before the mid-nineteenth century, there were basically two methods for making copies. Reproducing architectural drawings used to be a laborious process. Even today, how many times have you heard people say, or read in the popular press, ‘blueprints’ when referring to architectural drawings, regardless of whether copied or original? Specialists in the field must, of course, give latitude to such misuse, but when errors of medium such as ‘blueprint’ appear on exhibition labels or in academic books and articles, we question the curator or author’s knowledge of the architect’s methodology and therefore intent. In America during the last century, ‘blueprint’ became a general shorthand for all copied architectural drawings. But – and it may seem obvious to say – lines on paper are made by hand in an original, by equipment in a reproduction.Īn even more common error is to call architectural drawings ‘blueprints’. Original and copy drawings both physically consist of two elements: the material (like ink) and the support (usually paper). DMC 2272.2.Ī common error in looking at architectural drawings is to mistake mechanical reproductions for originals. – Neil Bingham Jean-Charles Moreux (1889–1956), Front Elevation, Design for a block of flats, Rue Gazan, Paris, c.1927. ![]()
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