what are blueprints

A blueprint is a two-dimensional set of drawings that provides a detailed visual representation of how an architect wants a building to look. Historically, blueprints were made to reproduce technical drawings through a contact print process on light-sensitive paper, and the blueprinting process enabled quick and accurate reproduction of specification drawings in the construction and building industry. The term "blueprint" is usually used to describe two printing methods, the blueprint and the diazotype. Blueprinting is the older method, invented in 1842, and the drawing to be copied, drawn on translucent paper, is placed against paper sensitized with a mixture of ferric ammonium citrate and potassium ferricyanide. The sensitized paper is then exposed to light, and where the areas of the sensitized paper are not obscured by the drawing, the light makes the two chemicals react to form blue. Nowadays, blueprints are often created digitally and can be used to communicate all the technical details of a project. Knowing how to read blueprints is an essential skill for professionals in the construction and building industry.