Blueprint
A blueprint is a reproduction of a technical drawing or engineering drawing using a contact print process on light-sensitive sheets introduced by Sir John Herschel in 1842.[1] The process allowed rapid and accurate production of an unlimited number of copies. It was widely used for over a century for the reproduction of specification drawings used in construction and industry. Blueprints were characterized by white lines on a blue background, a negative of the original. Color or shades of grey could not be reproduced.
For other uses, see Blueprint (disambiguation).
The process is obsolete, largely displaced by the diazo whiteprint process, and later by large-format xerographic photocopiers. It has almost entirely been superseded by digital computer-aided construction drawings.
The term blueprint continues to be used less formally to refer to any floor plan[2] (and even less formally, any type of plan).[3][4] Practising engineers, architects, and drafters often call them "drawings", "prints", or "plans".[5]
Digital[edit]
In most computer-aided design of parts to be machined, paper is avoided altogether, and the finished design is an image on the computer display. The computer-aided design program generates a computer numerical control sequence from the approved design. The sequence is a computer file which will control the operation of the machine tools used to make the part.
In the case of construction plans, such as road work or erecting a building, the supervising workers may view the "blueprints" directly on displays, rather than using printed paper sheets. These displays include mobile devices, such as smartphones or tablets.[14] Software allows users to view and annotate electronic drawing files. Construction crews use software in the field to edit, share, and view blueprint documents in real-time.[15]
Many of the original paper blueprints are archived since they are still in use. In many situations their conversion to digital form is prohibitively expensive. Most buildings and roads constructed before c. 1990 will only have paper blueprints, not digital. These originals have significant importance to the repair and alteration of constructions still in use, e.g. bridges, buildings, sewer systems, roads, railroads, etc., and sometimes in legal matters concerning the determination of, for example, property boundaries, or who owns (and/or is responsible for) a boundary wall.
