The History of the Blueprint
A blueprint is a reproduction of a technical based drawing. These technical based drawings are usually documenting an architectural or engineering design. Blueprints help the design turn into an actual building or machine.
In most recent years, the term “blueprint” has come to refer to any detailed plan. However, in its history, a blueprint was actually a blue! The process of making a blueprint was called a cyanotype chemical process. It was developed in 1842 by and astronomer named John Herschel. However, Anna Atkins brought this process to life with her series of cyanotype books that documented plant life. This same process was used for producing proofs in photography and offset printing for years to come.
Once discovered, this process was a low cost and effective solution for making copies of technical drawings. Since there was not any technical education involved in making blueprints, it was widespread and was immediately put to use in shipbuilding and the manufacture of railway locomotives.
Typically, a person wanting to make a blueprint would have a wooden frame with a spring-loaded back. This was much like a picture frame with a glass front. The drawing would be traced in India ink on tracing paper or cloth, depending on what the person wanted the final blueprint printed on. The coated paper and tracing would be loaded into the frame inside. It was then brought out to sunlight. Exposure time varied from less than a minute to about an hour, depending on the amount of sunlight that day. The operator could see the blue image appear through the tracing to determine when it was done. Then, the frame was brought indoors. The material was washed in running water to remove the unexposed coating and then dried thoroughly. It gave a clearly legible copy of the drawing with a white line on dark blue background. This copy possessed unlimited resistance to light and resistance to water that was as good as the original medium.
While blueprints were printed on a variety of substrates, they were most commonly printed on paper. However, more durable prints were done on linen until it was found that over time the linen would shrink and produce an out of scale drawing. After the invention of Mylar, it was used to print blueprints that needed to be more durable for long term use.
These traditional blueprints have been replaced by more modern printing methods and even digital displays of drawings. Presently, most prints are printed on oversized bond paper with a printer using a regular toner. These printers, toners and papers are designed and sold exclusively for blueprints and technical drawings. Most engineers and architects now have the ability to send a computer aided design directly to a printer or plotter and have a “blueprint” design in a matter of minutes. As print and display technology has advanced, the traditional term “blueprint” has continued to be used informally to refer to each type of image, even though these images are no longer produced chemically forming the print on a blue background.