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.
|Published (Last):||15 November 2004|
|PDF File Size:||18.77 Mb|
|ePub File Size:||3.6 Mb|
|Price:||Free* [*Free Regsitration Required]|
You may or may not feel the effects of overexposure, but know that you are being overexposed if drying with a hair dryer.
Introduction to gum bichromate printing – National Science and Media Museum blog
Try to start with negatives that have good not necessarily high contrast and density. Also, to rise to the challenge of the process, you will need to be bull-headed and persistent as there are so many variables and so much that can go wrong. If you are intending to make 10 x gim inch prints there is no problem.
Low density photographic negatives of the same size as the final image are used for exposing the print. Successful gum printing can be achieved through a careful management of the many variable factors associated with the process.
It is good for your first experiments. You will need to make contact prints and give more than one exposure if you wish to obtain bichrlmate wide range of tones with good gradation.
An introduction to the gum bichromate process
However, you may find the staining effect suitable for certain images. AKD-sized papers are my personal preference and have been for many years.
Start bichromaate a good negative: What I intend to do is give the recipe, details of the materials and their sources, the basic working method and a few useful hints. 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. Then, as you evaluate your progress, adjust only one or two of the knobs bichromatf a time.
Producing quality negatives ones that have adequate contrast and density and paper sizing are perhaps the most important variables to master, especially as you begin. Those factors include the following:. Read the health and safety instructions. Increasing the levels of light or dichromate, increases the insolubility of the materials which consequently, lessens the contrast.
Gum bichromate – Wikipedia
I reinvented the process for myself to keep it simple and avoid deadly poisons such as mercuric chloride which some use to kill off the bugs in the gum. The method you establish will reflect your own personality and way of working.
Indicate each step including how many coats, length of baths, and hardening agent for archival and personal purposes. Your email address will not be published. Leave a comment Cancel reply Pfocess email address will not be published. The negatives are then scanned and digitally printed to produce the enlarged negative. By Terry King on 5 May Introduction to gum bichromate printing. Then add about cm of watercolor from a tube.
Download this article as a printable pdf. Unless you enjoy plucking stray hairs out of your sticky emulsion, hake-style brushes might better be reserved for procss artistic purposes. A fan or a blow dryer set on the cool mode will help to speed the process along. The Museum cannot endorse or accept responsibility for the service offered by any supplier.
You might also consider using an imagesetter to make quality negatives. Water-soluble pigments Virtually any brand of watercolor will provide at least a few pigments that will be suitable for gum printing.
For larger sizes, use graphic arts films. 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.
The beginner gum bichromate printer would do well to study the works of those early masters. Many gum printers, including myself, prefer the hot press surface while others pfocess drawn to the cold press varieties. The information provided below proocess just one of many points of embarkment and offered to the reader as basic introductory material.
In closing, here are four helpful disciplines you may wish to include in your printing routine: This was when alternatives were being sought to the impermanent silver photograph.
Other material Rabbit procesd size, potassium metabisulphite from home made wine departments. As with all chemicals, treat them with respect. After exposure, the paper is placed in a series of plain water baths and allowed to develop until the unhardened portions of the emulsion have dissipated.
Handle with care and take proper safety precautions; keep out of reach of children; consult a Material Safety Data Sheet MSDS for further handling instructions.