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[[File:lighterstill.jpg]][[File:Blueprint1996_2.jpg|right|frame]]

[[File:lighterstill.jpg]][[File:Blueprint1996_2.jpg|right|frame]]

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.

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.

==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]] [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]].