A Combination Photography Process Explained
A favorite printing method of mine is to use a photography process called cyanotype combined with a second, more difficult process called gum bichromate. On their own, they are each interesting and have visual appeal. Together, they can create prints with uncommon attributes and a unique way of showing depth.
The primary method I use to blend these two processes is to print one layer of cyanotype completely and then print one layer of gum bichromate over it.
There are many types of alternative photography processes that exist and can be combined with each other; the possibility in this type of work is almost unlimited. This fact alone is one of the many reasons why I’m excited to share more with you about alternative processes and the beautiful chemical reactions they can create. Sometimes our large world seems small with all of the things that have already been discovered; it can seem like there’s nothing left to explore. When you divulge into a small niche, it can be invigoration and inspiring. Ultimately, I hope everyone can feel inspired to explore something new in their lives whether it be alternative photography or something else.
Washing unexposed chemical residue (yellow) off of an exposed cyanotype.
About Printing Cyanotypes
Cyanotype printing is a historically significant process that was previously used to create blueprints among other things. For more information on the history and uses of cyanotype, Wikipedia
has a great article, as well as AlternativePhotography
To create the typical cyanotype, potassium ferricyanide and ferric ammonium citrate are mixed to create a photosensitive solution that is used to coat paper and make the print. After the solution is brushed on to paper and exposed to light with a negative or to physical objects like flowers (also known as a sun print or even a photogram). After exposure to UV light, the print gets washed until all of the unexposed yellow coating is rinsed from the print and then it can be left to dry.
Left: An exposed gum bichromate print. Right: Washing unexposed chemicals from a gum bichromate print.
Printing with Gum Bichromate
Gum bichromate is the second layer of color, and is a fickle photographic process that was invented in 1839 which allows printing layers of different color. More information can be found on Wikipedia or at AlternativePhotograhy.
There are a few ways to make a gum bichromate, but the most common method is to mix gum arabic with potassium dichromate and your chosen dry pigment. These three substances are combined to create a light sensitive solution. Without the addition of pigment, this process will come out as a blank sheet when finished. After coating the paper with the sensitive chemical solution, the paper is exposed to UV light with a negative.
All processes pass through an initial washing stage, but with gum bichromate there is much more artistic control during the washing period verses other forms of photography.
During this bath treatment, one is able to use brushes, spray bottles, and other instruments to affect how the pigment layer is removed. This can make the final print look much different than the negative.
A paper negative created by oiling paper.
Negatives for the alternative photographic processes used at Huzz Art Shop are always the same size as the final print. Often I use camera-less art to create negatives with hand or computer made designs.