Cyanotype is a type of photographic printing process that results in a cyan-blue print. This process was extremely popular in the engineering world up into the twentieth century. Cyanotype printing is known for being inexpensive and simple, allowing for large-scale productions of work known as blueprints. The two main chemicals used in the process: potassium ferricyanide and ammonium iron citrate.
English astronomer and scientist John Herschel is responsible for developing this printing technique in 1842. Despite being credited with development of this technique, he mostly used the process in order to reproduce diagrams and notes, such as blueprints. It was artist Anna Atkins who originally began to use this for photographic purposes.
Atkins made a series of Cyanotype books. In the limited-edition productions, she recorded plant life. Atkins would place the different subjects onto coated paper, which made a silhouette result. Her use of this photographic technique earned her the title as the first female photographer.
In the usual Cyanotype procedure, equal amounts of ferric ammonium citrate and potassium ferricyanide are mixed together. This solution is mildly photosensitive. It is applied to a cloth, paper, or other receptive surface and given time to dry in an area that is dark. Cyanotypes may be printed on any surface that is capable of soaking up this iron solution, such as watercolor paper, wool and cotton.
Exposing the print to UV light, via a contact negative, is what produces the positive images. The ultraviolet light works by reducing the iron at level III to level II. This is then followed by a reaction of the iron II to the ferricyanide in the solution. The final result is known as a Prussian blue. Exposure to UV, such as sunlight, lowers the level of iron and in turn, changes the color of paper to a blue-light, steel-gray shade. The degree of color change is relevant to the total UV light.
When the exposure is complete, the picture is then developed by rinsing unreacted solution off. The blue color that shows up will darken as it dries up. Typically, the result that is sought out with this process is a blue shade. However, there are some effects and manipulations that can be done with this sort of process: toning, reducing, intensifying.
Reducing refers to the process of lowering the intensity of the final blue. Dektol, borax, TSP, Clorox, ammonia, carbonate and other such reagents may be used in this process. When applying reducers, it is important to pull the print from the weak solution and place it into a water bath to stop the bleaching process. Intensifying strengthens the blue color. To expedite oxidation of these prints, employ reagents such as lemon juice, vinegar, citric acid and hydrogen peroxide. Toning involves changing color of iron in a print. The change in color will vary based on the reagent applied. Tannic acid, cat urine, oolong tea, pyrogallic acid and wine are just some of the elements that may be used for this purpose.
Cyanotype printing has been used for hundreds of years. This printing technique involves using potassium ferricyanide and ammonium iron III citrate, as well as other chemicals, to produce blueprints. Many variations can be done with these prints. Anna Atkins is considered the first female photographer who introduced this print method to the photography industry.
English astronomer and scientist John Herschel is responsible for developing this printing technique in 1842. Despite being credited with development of this technique, he mostly used the process in order to reproduce diagrams and notes, such as blueprints. It was artist Anna Atkins who originally began to use this for photographic purposes.
Atkins made a series of Cyanotype books. In the limited-edition productions, she recorded plant life. Atkins would place the different subjects onto coated paper, which made a silhouette result. Her use of this photographic technique earned her the title as the first female photographer.
In the usual Cyanotype procedure, equal amounts of ferric ammonium citrate and potassium ferricyanide are mixed together. This solution is mildly photosensitive. It is applied to a cloth, paper, or other receptive surface and given time to dry in an area that is dark. Cyanotypes may be printed on any surface that is capable of soaking up this iron solution, such as watercolor paper, wool and cotton.
Exposing the print to UV light, via a contact negative, is what produces the positive images. The ultraviolet light works by reducing the iron at level III to level II. This is then followed by a reaction of the iron II to the ferricyanide in the solution. The final result is known as a Prussian blue. Exposure to UV, such as sunlight, lowers the level of iron and in turn, changes the color of paper to a blue-light, steel-gray shade. The degree of color change is relevant to the total UV light.
When the exposure is complete, the picture is then developed by rinsing unreacted solution off. The blue color that shows up will darken as it dries up. Typically, the result that is sought out with this process is a blue shade. However, there are some effects and manipulations that can be done with this sort of process: toning, reducing, intensifying.
Reducing refers to the process of lowering the intensity of the final blue. Dektol, borax, TSP, Clorox, ammonia, carbonate and other such reagents may be used in this process. When applying reducers, it is important to pull the print from the weak solution and place it into a water bath to stop the bleaching process. Intensifying strengthens the blue color. To expedite oxidation of these prints, employ reagents such as lemon juice, vinegar, citric acid and hydrogen peroxide. Toning involves changing color of iron in a print. The change in color will vary based on the reagent applied. Tannic acid, cat urine, oolong tea, pyrogallic acid and wine are just some of the elements that may be used for this purpose.
Cyanotype printing has been used for hundreds of years. This printing technique involves using potassium ferricyanide and ammonium iron III citrate, as well as other chemicals, to produce blueprints. Many variations can be done with these prints. Anna Atkins is considered the first female photographer who introduced this print method to the photography industry.
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