Difference between revisions of "Cyanotype"

From Camera-wiki.org
Jump to: navigation, search
(supply makers)
m (Refined Link URL)
 
(11 intermediate revisions by one other user not shown)
Line 1: Line 1:
<div class=floatleft>
+
{|class=floatleft
 +
|
 
{{Flickr_image
 
{{Flickr_image
 
|image_source= https://www.flickr.com/photos/uwe_kulick/16568266993/in/pool-camerawiki
 
|image_source= https://www.flickr.com/photos/uwe_kulick/16568266993/in/pool-camerawiki
 
|image= http://farm9.staticflickr.com/8684/16568266993_ed0f99f384_m_d.jpg
 
|image= http://farm9.staticflickr.com/8684/16568266993_ed0f99f384_m_d.jpg
|image_align= left
+
|image_align= center
 
|image_text= contact print from old b&amp;w 5&times;7"<br>glass plate negative - artist unknown.
 
|image_text= contact print from old b&amp;w 5&times;7"<br>glass plate negative - artist unknown.
 
|image_by= Uwe Kulick
 
|image_by= Uwe Kulick
 
|image_rights= wp
 
|image_rights= wp
}}&nbsp;&nbsp;</div>
+
}}
The cyanotype process is one of remarkable simplicity, producing a blue and white print on paper or cloth. It was invented in 1842 by Sir John Herschel.
+
|}
 +
__NOTOC__
 +
The cyanotype process is one of remarkable simplicity, producing a blue and white print on paper or cloth. It was invented in 1842 by Sir John Herschel. The first book of photographs was printed using this method!<ref>Atkins, Anna, British Algae: Cyanotype Impressions, privately printed (1843-53). A dozen copies are known to exist, see: Schaaf, L.J. and Kraus, H.P., Sun Gardens - Victorian photograms by Anna Atkins, (New York: Aperture Books 1985). </ref>  From 1870 to sometime in the 20th century, it was widely used as the "blueprint" method to copy technical drafts until photocopy methods made it obsolete.
 +
 
 +
Cyanotypes aren't silver-based as most other photo-chemical photographic processes, Cyanotypes are based on the chemical reaction that produces '''"Prussian Blue"''', between Ferricyanide and Iron (III) molecules, this reaction is accelerated by UV light, such as the UV in sunlight or "black light" lamps. Traditional cyanotype involves '''ferric''' ammonium citrate (NH<sub>4</sub>)<sub>5</sub>[Fe(C<sub>6</sub>H<sub>4</sub>O<sub>7</sub>)<sub>2</sub>]  and potassium '''ferricyanide''', K<sub>3</sub>[Fe(CN)<sub>6</sub>]  potassium dichromate is used as an additive, to increase sensitivity and contrast.  Newer versions of this process use Ammonium Iron(III) Oxalate as ferric salt which gives it more sensititivy and longer life.  Traditional cyanotype is very sensitive to alkali and it fades over time in darkness, a reexposure to light makes it reappear.
  
From 1870 to sometime in the 20th century, it was commonly used as the "blueprint" method to copy technical drafts. The used chemicals aren't silver-based as those of most other photo-chemical photographic processes, and their sensitivity is mostly to ultraviolet, such as the UV in sunlight. The paper can be prepared under incandescent light. Solutions of the method's iron-based chemicals are applied to paper surfaces or cloth, which can then be printed on when they are dry. The chemicals involved are ferric ammonium citrate and potassium ferricyanide, AKA pot ferri.
+
The paper can be prepared under incandescent light (no UV), by applying the sensitizer solution directly to the paper, cloth or other media, which can then be printed on dry. Applying more than 1 coat of sensitizer makes the image a deeper tone of blue.
  
It is a printing-out process: the image formed by the light is visible, not latent, and so there is no strict "development" stage. Instead, excess emulsion is washed away by running water. Toning can be done to increase or decrease the intensity of the blue and/or the contrast.
+
It is a printing-out process: the image formed by the light is visible, not latent, and the exposure can be estimated by the changes in color of the emulsion.  There is no strict "development" stage, instead, excess emulsion is washed away by running water. Washing in a diluted acetic acid solution (0.5-1.5%) increases the midtone density and the color looks brighter<ref>[https://www.alternativephotography.com/vinegar-developed-cyanotypes-non-toxic-midtone-contrast-control/ Using Vinegar to develop cyanotypes]</ref>.
 +
Toning can be applied to increase or decrease the intensity of the blue and/or the contrast.
  
 
A common use is to make photograms: opaque objects with interesting shapes are laid on the sensitized paper, and then the paper is put in direct sunlight or under an ultraviolet lamp, for a time usually measured in minutes (quality of sunlight or brightness of the UV lamp is a factor.)
 
A common use is to make photograms: opaque objects with interesting shapes are laid on the sensitized paper, and then the paper is put in direct sunlight or under an ultraviolet lamp, for a time usually measured in minutes (quality of sunlight or brightness of the UV lamp is a factor.)
  
Of course, this can also be done with [[large format|large]] or [[medium format]] negatives, or ink on tracing paper. The latter is how blueprints were made when the process was in vogue. A drafter would draw the plans on paper in pencil, then trace it in ink on tracing paper. This would then be used as a negative, to produce positive copies made of white lines on a Prussian Blue background. This was done for several reasons, the main being that it was cheap, could make any number of copies, and was very difficult to alter once printed.  In the digital age, a hybrid process is possible, my making digital negatives, using a printer and either transparency film or paper.
+
Of course, this can also be done with [[large format|large]] or [[medium format]] negatives, or ink on tracing paper. The latter is how blueprints were made when the process was in vogue. A drafter would draw the plans on paper in pencil, then trace it in ink on tracing paper. This would then be used as a negative, to produce positive copies made of white lines on a Prussian Blue background. This was done for several reasons, the main being that it was cheap, could make any number of copies, and was very difficult to alter once printed.   
 +
 
 +
Cyanotypes can be [[toning|toned]] using several methods, a common one is to use tannins, such as the ones found in tea or coffee.  This has the effect of increasing the permanence of the images. 
 +
In the direct method the image turn gray-blue and the paper will be stained as well, in the indirect method the amount of bleach determines the final color, in hues from gray blue to brown.
 +
{| class = floatright
 +
|
 
{{Flickr_image
 
{{Flickr_image
 
|image_source=https://www.flickr.com/photos/titrisol/52263758149/in/pool-camerawiki
 
|image_source=https://www.flickr.com/photos/titrisol/52263758149/in/pool-camerawiki
|image=https://live.staticflickr.com/65535/52263758149_67f8b29744_q.jpg
+
|image=https://live.staticflickr.com/65535/52263758149_720906c2f4_q.jpg
|image_align= right
+
|image_align= center
|image_text= Digital negative used for contact print of cyanotype
+
|image_text= Using a digital negative <br> during contact print <br> and finished image
 
|image_by= Pablo Coronel
 
|image_by= Pablo Coronel
 
|image_rights= wp
 
|image_rights= wp
 
}}
 
}}
 +
|}
 +
As cyanotype is a cheap way of making contact prints, it still survives to this day under the heading of an "alternate process." Unfortunately, it is extremely difficult to make enlargements on cyanotype: most enlarger lenses are not designed to transmit ultraviolet light, and most enlargers do not take any common ultraviolet bulb. Thus, it is somewhat limited to the realm of contact prints and photograms.
  
Cyanotypes can be [[toning|toned]] using several methods, a common one is to use tannins, such as the ones found in tea or coffee. This has the effect of increasing the permanence of the images.
+
In the digital age, cyanotype has seen a rebirth as a hybrid technique <ref>[https://www.alternativephotography.com/digital-hybrids-a-new-twist-on-an-old-process/ Hybrid method description at Alternative Photography ]</ref>, i.e. using '''digital negatives''', made in a printer using either transparency film or paper which are contact printed in the traditional method.  Digital negatives can be made in almost any size, only limited by the printer.
 
 
As cyanotype is a cheap way of making contact prints, it still survives to this day under the heading of an "alternate process." Unfortunately, it is extremely difficult to make enlargements on cyanotype: most enlarger lenses are not designed to transmit ultraviolet light, and most enlargers do not take any common ultraviolet bulb. Thus, it is somewhat limited to the realm of contact prints and photograms.
 
  
 +
These digital negatives <ref>[https://www.alternativephotography.com/digital-negatives/ A simplified digital negatives workflow] by Christina Z. Anderson and Ron Reeder at alternative photography (2013) </ref> are prepared in software and can be modified in many ways to obtain the desired final image.  The digital negatives have greater control than traditional silver negatives, and they use "curves" to adjust the contrast to match the specific process <ref>[https://www.precisiondigitalnegatives.com/table-of-contents.html ebook on digital negatives] by Mark I. Nelson</ref>
 
{{br}}
 
{{br}}
  
Line 37: Line 49:
 
*[https://stores.photoformulary.com/ Photographer's formulary] (process kit)
 
*[https://stores.photoformulary.com/ Photographer's formulary] (process kit)
 
{{br}}
 
{{br}}
 +
 +
==Notes==
 +
<references/>
 +
 +
==Bibliography==
 +
Ware, Mike. Cyanomicon  The History, Science and Art of Cyanotype: Photographic Printing in Prussian Blue.  Science Museum of London . 1999.  Available directly from [https://www.mikeware.co.uk/mikeware/downloads.html the author ]
  
 
==Links==
 
==Links==
 
*[http://www.mikeware.co.uk/mikeware/New_Cyanotype_Process.html "New Cyanotype Process"], (toxic) aspects of modern methods to improve the old process. 1996/2004 by [http://www.mikeware.co.uk/ Mike Ware]
 
*[http://www.mikeware.co.uk/mikeware/New_Cyanotype_Process.html "New Cyanotype Process"], (toxic) aspects of modern methods to improve the old process. 1996/2004 by [http://www.mikeware.co.uk/ Mike Ware]
 
*[https://www.flickr.com/groups/61907246@N00/ flickr group "Cyanotypes"]
 
*[https://www.flickr.com/groups/61907246@N00/ flickr group "Cyanotypes"]
 +
*[https://www.alternativephotography.com/curve-corner-photoshop-curves/ Curves for adjusting digital negatives]
  
 
[[category:Photographic processes]]
 
[[category:Photographic processes]]

Latest revision as of 05:32, 11 February 2023

The cyanotype process is one of remarkable simplicity, producing a blue and white print on paper or cloth. It was invented in 1842 by Sir John Herschel. The first book of photographs was printed using this method![1] From 1870 to sometime in the 20th century, it was widely used as the "blueprint" method to copy technical drafts until photocopy methods made it obsolete.

Cyanotypes aren't silver-based as most other photo-chemical photographic processes, Cyanotypes are based on the chemical reaction that produces "Prussian Blue", between Ferricyanide and Iron (III) molecules, this reaction is accelerated by UV light, such as the UV in sunlight or "black light" lamps. Traditional cyanotype involves ferric ammonium citrate (NH4)5[Fe(C6H4O7)2] and potassium ferricyanide, K3[Fe(CN)6] potassium dichromate is used as an additive, to increase sensitivity and contrast. Newer versions of this process use Ammonium Iron(III) Oxalate as ferric salt which gives it more sensititivy and longer life. Traditional cyanotype is very sensitive to alkali and it fades over time in darkness, a reexposure to light makes it reappear.

The paper can be prepared under incandescent light (no UV), by applying the sensitizer solution directly to the paper, cloth or other media, which can then be printed on dry. Applying more than 1 coat of sensitizer makes the image a deeper tone of blue.

It is a printing-out process: the image formed by the light is visible, not latent, and the exposure can be estimated by the changes in color of the emulsion. There is no strict "development" stage, instead, excess emulsion is washed away by running water. Washing in a diluted acetic acid solution (0.5-1.5%) increases the midtone density and the color looks brighter[2]. Toning can be applied to increase or decrease the intensity of the blue and/or the contrast.

A common use is to make photograms: opaque objects with interesting shapes are laid on the sensitized paper, and then the paper is put in direct sunlight or under an ultraviolet lamp, for a time usually measured in minutes (quality of sunlight or brightness of the UV lamp is a factor.)

Of course, this can also be done with large or medium format negatives, or ink on tracing paper. The latter is how blueprints were made when the process was in vogue. A drafter would draw the plans on paper in pencil, then trace it in ink on tracing paper. This would then be used as a negative, to produce positive copies made of white lines on a Prussian Blue background. This was done for several reasons, the main being that it was cheap, could make any number of copies, and was very difficult to alter once printed.

Cyanotypes can be toned using several methods, a common one is to use tannins, such as the ones found in tea or coffee. This has the effect of increasing the permanence of the images. In the direct method the image turn gray-blue and the paper will be stained as well, in the indirect method the amount of bleach determines the final color, in hues from gray blue to brown.

As cyanotype is a cheap way of making contact prints, it still survives to this day under the heading of an "alternate process." Unfortunately, it is extremely difficult to make enlargements on cyanotype: most enlarger lenses are not designed to transmit ultraviolet light, and most enlargers do not take any common ultraviolet bulb. Thus, it is somewhat limited to the realm of contact prints and photograms.

In the digital age, cyanotype has seen a rebirth as a hybrid technique [3], i.e. using digital negatives, made in a printer using either transparency film or paper which are contact printed in the traditional method. Digital negatives can be made in almost any size, only limited by the printer.

These digital negatives [4] are prepared in software and can be modified in many ways to obtain the desired final image. The digital negatives have greater control than traditional silver negatives, and they use "curves" to adjust the contrast to match the specific process [5]

supply makers


Notes

  1. Atkins, Anna, British Algae: Cyanotype Impressions, privately printed (1843-53). A dozen copies are known to exist, see: Schaaf, L.J. and Kraus, H.P., Sun Gardens - Victorian photograms by Anna Atkins, (New York: Aperture Books 1985).
  2. Using Vinegar to develop cyanotypes
  3. Hybrid method description at Alternative Photography
  4. A simplified digital negatives workflow by Christina Z. Anderson and Ron Reeder at alternative photography (2013)
  5. ebook on digital negatives by Mark I. Nelson

Bibliography

Ware, Mike. Cyanomicon The History, Science and Art of Cyanotype: Photographic Printing in Prussian Blue. Science Museum of London . 1999. Available directly from the author

Links