Blueprint

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For other uses, see Blueprint (disambiguation).

Modern blueprint of the French galleon La Belle.

A blueprint is a type of paper-based reproduction usually of a technical drawing documenting an architecture or an engineering design. More generally, the term "blueprint" has come to be used to refer to any detailed plan.

1 Etymology
2 History
3 Use
4 Replacements for blueprints
5 Blueprint companies
6 See also
7 External links

[edit] Etymology

The term "blueprint" was originally derived from the visual aspects of prints made using the contact printing process of cyanotype. It is cyanotype which produces the white lines on blue background which are characteristic of the traditional blueprint.

[edit] History

The blueprint process was developed by the British astronomer Sir John Herschel in 1840. The photosensitive compound, a solution of ammonium ferric citrate and potassium ferricyanide, is coated onto paper. Areas of the compound exposed to strong light are converted to insoluble blue ferric ferrocyanide, or Prussian blue. The soluble chemicals are washed off with water leaving a light-stable print.

A similar process was used to produce printing proofs for offset printing.

Various materials have been used for blueprints. Paper was a common choice, but for more durable prints linen was sometimes used, but with time, the linen prints would shrink slightly. To combat this problem, printing on vellum and, later, mylar was implemented.

[edit] Use

A blueprint had several advantages over other types of drawings; the contact printing method allowed an unlimited number of prints to be made without degradation and assured highly accurate dimensions on the copies. The resulting prints were resistant to fading, marking, and alteration. Additionally, the blueprint process was significantly less expensive than a silver-based photographic process.

Revision control was done in contrasting color on the blueprints, for example red markup of a blueprint copy by the engineer, then yellow markup on the copy by the draftsman who implemented the changes on the original drawing, then brown markup by the checker, on a check-print (a brown-line) or sepias. Finally, the architect or engineer, draftsman, checker and supervisor would sign the original drawing, thus making it a legal document. This final, approved drawing would become the original from which new blueprints were made.

[edit] Replacements for blueprints

Traditional blueprints have largely been replaced by more modern, less expensive printing methods and digital displays. In the early 1940s, cyanotype blueprint began to be supplanted by Diazo prints or whiteprints, which have blue lines on a white background; thus these drawings are also called blue-lines or bluelines. Other comparable dye-based prints are known as blacklines.

Diazo prints remain in use in some applications but in many cases have been replaced by Xerographic print processes similar to standard copy machine technology using toner on bond paper. More recently, designs created using Computer-Aided Design techniques may be transferred as a digital file directly to a printer; in some applications paper is avoided altogether and work and analysis is done directly from digital displays.

As print and display technology has advanced, the traditional term "blueprint" has continued to be used informally to refer to each type of image.

[edit] Blueprint companies

New York City has been a center of the blueprinting industry for the past century.^{[citation needed]} Although the industry has converted to the whiteprinting system, the companies have primarily stayed the same. Among the largest as of 2006 is BP Independent Reprographics, which is the result of several mergers and buyouts between Independent Blueprinting, Crown Reproductions, and The Blueprint Company. The New York City blue printers communicate via the Manhattan Blue Printers’ Association.

Seattle has also been a growth area of the reprographics industry. Although most reprographics houses have been purchased by American Reprographics Company (ARC), some have remained independent. Among them are University Reprographics in Seattle, and Bill's Blueprint in Everett. ARC is also the company behind Planwell, which focuses on the architecture, engineering and construction market.