What are blueprints, and why are they blue?

Answer 1

"blueprints" came from the machine that was once used to reproduce original pen and ink construction plans. The device was called a Blu Ray. It used a reaction caused by amonia to transfer a copy from the original. If you have ever seen an OLD set of blueprints/construction plans you would see the obvious answer to you rquestion.

Answer 2

Blueprints are copies of the original drafted plans to build something. The original process for copying made a sheet with a blue background (for the white part of the original) and white for the black lines. It was thought this arrangement would hold up better to fading. Later, the copies made were more like the original, white background and blue lines. Now, very few people still use this process, with a Xerox like process being now the predominate copying mode. The name for these copies has not changed though.

Answer 3

A blueprint is, conceptually, a plan or design documenting an architecture or an engineering design. While this may be as simple as a quick sketch or outline using pencil and paper, a blueprint is traditionally reflected as the contact printing process of cyanotype. It is cyanotype which produces the familiar white lines on blue background. The term is often used metaphorically to mean any detailed plan.

Answer 4

Warren has it. The blueprint process of making prints uses ammonia which is far cheaper than the chemicals in photographic processes of years past.

Answer 5

They are the schematic drawings of buildings, like an architect does. They are blue because even though the paper starts out white, the process of running them through the old-style copiers turned the paper blue, and left the areas where the ink was white. The copiers used 100% ammonia, and Jeez did it smell! (My parents own an architectural firm). Luckily, up-to-date copiers don't use ammonia, and the paper stays white.

Answer 6

Plans... because white is easier to distinguish on a blue background

Answer 7

1. Something intended as a guide for making something else

2. Photographic print of plans or technical drawings etc.

Answer 8

It's because years ago that was the cheapest way to produce an image.