Terry King gives an overview of gum bichromate printing, along with a step-by- step guide to the process. Fifteen years ago, I was in a similar. Gum bichromate process definition, a contact printing method in which the image is formed on a coating of sensitized gum containing a suitable colored pigment. In the late s, pictorialist photographers favored a diversity of photographic techniques, including the gum dichromate process. Sometimes superimposed.
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I cannot any longer aford large film negs. Simply repeat steps 2 through 8. It is good for your first experiments.
This information has been collated as a service for enquirers. Either compound can be purchased in a bright orange crystal granular form from a chemical supplier. You will need to have negatives the same size as your final print. Again, the gum bichromate emulsion is essentially a modified watercolor. This can be seen on the reverse of the paper as a yellow stain where pigment was applied on the verso. There are many other ways of making a gum print.
Well that was fairly simple; remembering these principles should enable you to answer most of the problems that the process throws up. Several changes of water bath are necessary to clear the print.
How fun to know that you have begun to work in gum printing. Sorry, your blog cannot share posts by email. The more pigment you use the less chance the light has to do its work.
Potassium dichromate K2Cr can be dissolved to the extent of one part in eleven in water. My preference favors a potassium solution.
Gum Bichromate Process | NINIANE KELLEY PHOTOGRAPHY
The information provided below is just one of many points of embarkment and offered to the reader as basic introductory material. You will find that some variables, such as paper and pigment batches, change without warning requiring major adjustments to bichrlmate made to other knobs on the console.
Other methods depend upon cumulative misreadings and misunderstandings of writers on the subject for the proceess years. Eventually they overcame, in varying degrees, the myriad of pitfalls encountered on the road to creating wonderful prints. You may need to switch to a dry brush to help smooth the emulsion.
Stretching pre-shrinking paper is necessary if you are printing more than one color or multiple times with the same color to build up density. It is then up to you to go away and make your gum print. Low density photographic negatives of the same size as the final image are used for exposing the print. Paper formulations can change, often without notice, greatly affecting the quality of your work. Gouache was added as the final touch.
Gum bichromate – Wikipedia
A heavy weight cotton watercolor or printmaking paper that can withstand repeated and extended soakings is best. A poor print is usually the result of failing to control one or more variables.
Alphonse Poitevin added carbon pigment to the colloids increating the first carbon print. Let me know how you progress! In this way you can easily trace your steps to find mistakes or places to improve your printing. Make a test exposure on the small sheet using a Stouffer scale to determine correct exposure time for your light source. You can buy a very expensive version in lumps, together with bits of tree, which is known as royal gum arabic.
An introduction to the gum bichromate process
My immediate reaction was that, if he could do that in black and white, there must be a whole new world out there, in colours, that I could choose for myself. Others satisfy the need of the proponents for complication.
They are cancer suspect agents.