Yes. The blueprint is a technical drawing of an architectural or engineering design. It is a large drawing with white lines on a white background.
The process of blueprinting was invented in the 1800s. It was a cheap and simple method of reproducing large drawings.
The design is drawn on tracing paper and placed on a paper that is chemically treated with a mixture of ammonium iron citrate and potassium ferrocyanide. The double paper is exposed to bright light for several minutes as a result o which the treated paper turns a brilliant Prussian Blue except in the parts covered by the drawn lines. The paper is then washed and dried, yielding a blue-coloured negative of the original drawing.
Nowadays, newer and more sophisticated methods are used to produce blueprints, but they are not blue like the traditional prints.
Picture Credit : Google