Changes

==History==

==History==

The blueprint [[process]] is essentially the cyanotype process developed by the British [[astronomer]] [http://en.wikipedia.org/wiki/John_Herschel John Herschel] in 1842.[1] The photosensitive compound, a solution of ferric ammonium citrate and [http://en.wikipedia.org/wiki/Potassium_ferricyanide potassium ferricyanide], is coated onto paper. Areas of the compound exposed to strong [[light]] are converted to insoluble blue ferric ferrocyanide, or [http://en.wikipedia.org/wiki/Prussian_blue Prussian blue]. The soluble [[chemicals]] are washed off with water leaving a light-stable [[print]].

The blueprint [[process]] is essentially the cyanotype process developed by the British [[astronomer]] [https://en.wikipedia.org/wiki/John_Herschel John Herschel] in 1842.[1] The photosensitive compound, a solution of ferric ammonium citrate and [https://en.wikipedia.org/wiki/Potassium_ferricyanide potassium ferricyanide], is coated onto paper. Areas of the compound exposed to strong [[light]] are converted to insoluble blue ferric ferrocyanide, or [https://en.wikipedia.org/wiki/Prussian_blue 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.

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

Various base [[materials]] have been used for blueprints. [[Paper]] was a common [[choice]]; for more durable prints linen was sometimes used, but with [[time]], the linen prints would shrink slightly. To combat this problem, printing on imitation vellum and, later, polyester film ([http://en.wikipedia.org/wiki/Mylar Mylar]) was implemented.

Various base [[materials]] have been used for blueprints. [[Paper]] was a common [[choice]]; for more durable prints linen was sometimes used, but with [[time]], the linen prints would shrink slightly. To combat this problem, printing on imitation vellum and, later, polyester film ([https://en.wikipedia.org/wiki/Mylar Mylar]) was implemented.

==Use==

==Use==

For almost a century blueprint was the only low cost process available for copying [[drawings]]. Once invented, no technical development was required; the [[process]] was put to widespread use immediately, notably in shipbuilding and the manufacture of railway locomotives and rolling stock.

For almost a century blueprint was the only low cost process available for copying [[drawings]]. Once invented, no technical development was required; the [[process]] was put to widespread use immediately, notably in shipbuilding and the manufacture of railway locomotives and rolling stock.

The coated material ready for use has a shelf life of two days. Industrial areas would often have many independent suppliers that made blueprint coated materials to order and provided a copying service.

The coated material ready for use has a shelf life of two days. Industrial areas would often have many independent suppliers that made blueprint coated materials to order and provided a copying service.

The typical [[practice]] was to have a wooden frame with a spring-loaded back, similar to a picture frame with a glass front. The drawing would be traced in [http://en.wikipedia.org/wiki/India_ink India ink] on tracing [[paper]] or tracing cloth. Indoors, the coated paper and tracing would be loaded into the frame which was then brought out to sunlight. Exposure time varied from less than a minute to about an hour (under an overcast sky). The operator could see the blue image appear through the tracing. When ready the frame was brought indoors. The material was washed in running water to remove the unexposed coating, then dried. It gave a clearly legible copy of the drawing with a white line on dark blue background. This copy possessed unlimited [[resistance]] to [[light]] and resistance to water that was as good as the substrate.

The typical [[practice]] was to have a wooden frame with a spring-loaded back, similar to a picture frame with a glass front. The drawing would be traced in [https://en.wikipedia.org/wiki/India_ink India ink] on tracing [[paper]] or tracing cloth. Indoors, the coated paper and tracing would be loaded into the frame which was then brought out to sunlight. Exposure time varied from less than a minute to about an hour (under an overcast sky). The operator could see the blue image appear through the tracing. When ready the frame was brought indoors. The material was washed in running water to remove the unexposed coating, then dried. It gave a clearly legible copy of the drawing with a white line on dark blue background. This copy possessed unlimited [[resistance]] to [[light]] and resistance to water that was as good as the substrate.

The [http://en.wikipedia.org/wiki/Whiteprint diazo] document copying process progressively took over from blueprint during the period 1935 to 1950.

The [https://en.wikipedia.org/wiki/Whiteprint diazo] document copying process progressively took over from blueprint during the period 1935 to 1950.

==See also==

==See also==

*'''''[[Architects of the Master Universe]]'''''

*'''''[[Architects of the Master Universe]]'''''

==Further reading==

==Further reading==

[http://books.google.com/books?id=09_Sr9emceQC&pg=PA113 "Man And His Machines: Electric Blue Printing Machine"]. [http://en.wikipedia.org/wiki/World%27s_Work The World's Work: A History of Our Time] XXXI: 113. November 1915. http://books.google.com/books?id=09_Sr9emceQC&pg=PA113. Retrieved 2009-08-04.  

[https://books.google.com/books?id=09_Sr9emceQC&pg=PA113 "Man And His Machines: Electric Blue Printing Machine"]. [https://en.wikipedia.org/wiki/World%27s_Work The World's Work: A History of Our Time] XXXI: 113. November 1915. https://books.google.com/books?id=09_Sr9emceQC&pg=PA113. Retrieved 2009-08-04.  

==External links==

==External links==

* [http://www.the-blueprints.com/ The-Blueprints.com] - The largest free blueprint/3-view/template collection on the internet, with over 36000 images online.

* [https://www.the-blueprints.com/ The-Blueprints.com] - The largest free blueprint/3-view/template collection on the internet, with over 36000 images online.

[[Category: Prints]]

[[Category: Prints]]

[[Category: General Reference]]

[[Category: General Reference]]