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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Often just a minor adjustment of one or two knobs will make a big difference. Eventually they overcame, in varying degrees, the myriad of pitfalls encountered on the road to creating wonderful prints.
Most of what is presented comes from twenty pocess of personal experience, and perhaps a bias or two picked up along the way. Make lots of sized paper at one time. UV health lamps also work. And if that is the peak of your ambition, then fine. High quality prints are possible without any additional sizing.
Without stretching, the paper will change shape between layer printings.
Why let your paper soak unnecessarily in dichromate that otherwise can easily be removed by a brief initial rinse? Witness, too, the plethora of new publications devoted to the subject of gum printing and the increasing number of exhibitions featuring both monochrome and tricolor prints.
Terry King gives an overview of gum bichromate printing, along with a step-by-step guide to the process. Refrigerate to extend its shelf life thereby reducing the need to add a preservative.
Introduction to gum bichromate printing – National Science and Media Museum blog
How fun to know that you have begun to work in gum printing. Afterward, it is usually recommended that another coat be applied of the gmu color or perhaps another color over top of the first layer to help improve the tonal range and density of the print. Lith and line films can be used but they should be exposed and developed for continuous tone unless you are looking for line results.
The beginner bicgromate bichromate printer would do well to study the works of those early masters.
A staining pigment will stain the whole of the image area. You will find that some variables, such as paper and pigment batches, change without warning requiring major adjustments to be made to other knobs on the console. Download this article as a printable pdf. Store finished solution in a light-tight bottle. The information provided bichrokate is just one of many points of embarkment and offered to the reader as basic introductory material.
In closing, here are four procews disciplines you may wish to include in your printing routine: I avoid problems of sizing and lack of lateral stability by using papers that are adequately sized and of adequate weight.
Gum Bichromate Process | NINIANE KELLEY PHOTOGRAPHY
They are bixhromate suspect agents. Gloy gum is PVA with surfactants; it is three times as fast but not so easily controlled. This was when alternatives were being sought to the impermanent silver photograph. The dichromate molecule can be excited by light at the right wavelength to throw one of its oxygen atoms which fills in the gaps between the spurs on the gum molecule chain.
White gum arabic powder, diluted 1: For many years and occasionally still I made negatives using the analogue method of enlarging medium format transparencies onto orthochromatic film. Indicate each step including how many coats, length of baths, and hardening agent for archival and personal purposes.
Bichtomate light source will harden the dichromate in proportion to the densities of your negative. I developed the film in dilute Dektol 1: Consult a paper supplier proess the manufacturer for current information.
Gum Bichromate Process
The negatives are then scanned and digitally printed to produce the enlarged negative. Indeed, a properly made negative is one more key, among the many keys, to creating technically and esthetically pleasing prints.
The variables become more manageable while the image quality is virtually identical. prcess
Afterwards, the print is hung to dry. Each layer must be fully processed and dried before subsequent layers can be applied.
Both papers are PH neutral and archivally sound. Put in terms that I can understand, the gum molecule is a flexible chain of hydrogen and carbon atoms with oxygen side spurs. Increasing the levels of light or dichromate, increases processs insolubility of the materials which consequently, lessens the contrast.
This page was last edited on 30 Decemberat It is an essential key to quality gum printing. For your beginning work try cadmiums, cobalts, ultramarines, earth pigments, and lamp black.
You might try a mixture of Prussian Blue with Burnt Sienna as an alternative to single black pigments. After exposure and development, the insolubilised gum, which is porous, retains bicyromate solid particles of pigment, while any remaining dichromate in procees is washed away.
A simple duotone separation combining orange watercolor pigment and a cyanotype can yield surprisingly beautiful results. I, for my part, went to a talk by a gentleman from Maidenhead called Steinbock.
But the technique of this bicromate and white print gave it a power, a hyper-reality that seemed to outshine so many of the silver gelatin prints I had seen. Consider the variables above you will discover others as control knobs on a console.
The prints are made on Arches Platine paper, sized with gelatin. I have been doing my first prints.