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, 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. The blueprint process was characterized by white lines on a blue background, a negative of the original. The process was not able to reproduce color or shades of grey.

The process is now obsolete. It was first largely displaced by the diazo whiteprint process, and later by large-format xerographic photocopiers. 这个过程现在已经过时了。它最初主要被重氮白印工艺取代，后来被大幅面静电复印机取代。

The term blueprint continues to be used less formally to refer to any floor plan (and even less formally, any type of plan). Practicing engineers, architects, and drafters often call them "drawings" or "prints".

In the early 1940s, cyanotype blueprint began to be supplanted by diazo prints, also known as whiteprints. This technique produces blue lines on a white background. 在20世纪40年代早期，蓝版蓝图开始被重氮印刷取代，也被称为白印。这种技术在白色背景上产生蓝线。

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. Software allows users to view and annotate electronic drawing files.

六级/考研单词: blueprint, reproduce, rapid, construct, shade, gray, displace, seldom, compute, numerical, erect, supervise, mobile, hardware, electron