Why are blueprints blue and not some other color? There's a specific chemical process behind it, and its discovery has all the elements of a dark fairy tale. A blueprint is a paper-based reproduction of a technical drawing, such as an architectural plan or an engineering design, historically used to create accurate copies of original documents. The term itself refers directly to the distinctive white.
Blueprints are an older style of drawing that is now totally obsolete. They were used because scientists had discovered a certain type of chemical that turned blue after it had been exposed to air. Why are blueprints no longer blue? Learn about how the process of creating architectural documents has evolved since the 19th century.
Making copies of architectural drawings hasn't always been the easiest thing in the world to do. For the majority of human history, the most economical solution was simply to have someone make a tracing of the original plans. In the mid-nineteenth century, the process abruptly became much quicker and easier thanks to famed polymath Sir John Herschel.
In 1842, Herschel invented a method to. For many years, blueprints have been associated with architectural, engineering, and technical drawings. We instantly recognize their distinctive blue background with white lines, but few people.
In America during the last century, 'blueprint' became a general shorthand for all copied architectural drawings. 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? The term "blueprints" is often associated with a specific color, but do they actually have to be blue? The answer is no, blueprints do not have to be blue.
In fact, the color of a blueprint has changed over time, and modern blueprints are often printed in various colors depending on the specific needs of the project. Can a blueprint not be blue? More recently, the diazo whiteprint process and large-format xerographic photocopiers have largely replaced blueprinting even for these specialized purposes, and many "blueprints" are now black or grey lines on a white background. The methods described above, though still used, are old and have given way to more sophisticated techniques.
Whereas blueprint reproductions are negatives of an original drawing, the diazo (whiteprinting) process provides positive images like those of blue-line prints, except the lines can be of almost any color on a white background.