I set up a paper studio with the help of Joop Persoon, the head of the fiber laboratory of the Royal Dutch Papermills (KNP) in Maastricht. He still advises me on papermaking techniques. Following his suggestion I now use a German-built Voigt hollander beater, a completely closed, high-speed lab model which throws the pulp over and under the roller.
Papermaking in itself became so important to me as a medium that printmaking was forgotten for about ten years. During this time I developed different kinds of vacuum formers which enabled me to make sheets of unlimited size and thickness.(1) At one point I wondered if vacuuming the pulp onto an etching plate would yield a print, but discovered that the pressure I was able to obtain was inadequate. I continued to work in this direction after the printing ink was out of the cupboard. After one year of working on hunches, I found, to my own great surprise, a completely new way of transferring ink to paper.
The materials used in this process are: a regular zinc etching plate; oil-based etching ink (metal oxide pigments work best); and freshly beaten cotton fiber. I use cotton linters beaten in the hollander for about an hour. I have tried other fibers but cotton gives me the best result because it has great capillary action in drying. After an hour of beating, it makes a great blotter and at the same time is strong enough to withstand the pulling and tearing which sometimes need to be done to remove the paper from the zinc plate.
I prefer using oil-based printing inks for this technique because the water-based inks which I have tried work very unpredictably. The binders in these inks dry much faster than oils, and so the paper often sticks to the zinc. I have also tried other metals like aluminum and copper, but nothing works as well as zinc.
I cut my zinc plates with a figuresaw so that I can make an assemblage of image fragments, at different heights and angles, to be surrounded by paper. An image is etched into the plate which is then inked in the classic way. Very wet paper pulp is then poured over it. The pulp must be watery enough so that it flows evenly and is as thin as possible. At the same time the zinc plate should be covered completely. This means waiting for the water to drain and the pulp to settle on the plate and then adding a new layer of pulp. This is repeated until the plate is completely covered. The pulp is covering the image, so the process requires quite a bit of foresight, as one is working from the bottom up.
When I place my zinc plates at an angle I support them with plaster so that atmospheric pressure does not flatten them when they are dried using a vacuum table. A problem with pulp running off the plate when the angle is steep is one I have not yet solved to my satisfaction. I have had success, however, with half-drying the pulp on plates laid flat and then positioning them at the desired angle while incorporating them into the total piece.
Zinc and normal hard tap water or, even better, salt water create a state in which an electric current will appear. The current is supported by the impurities in the water, and so distilled water does not work. I have measured 0.7 volts between the zinc and the wet pulp. The pulp is negative and the zinc is positive.
The electrical current causes the surface of the zinc plate to dissolve, a process called electrolysis. For as long as the current lasts, the top layer of zinc and the printing ink on it will be separated from the main body of zinc. The bonding force caused by the water, migrating through the pulp to the surface where it evaporates, is so strong that it draws and adheres the ink to the paper pulp. This is a very critical phase because the forces which are at work complement each other. The first drying is done on a vacuum table; after that I use a fan and sometimes a heatlamp.
I found it best to work with as thin a layer of pulp as possible and to use forced air to dry the pulp within a day. If the pulp stays wet too long the corrosion on the zinc will become so bad that it will cake to the pulp. The paper and the zinc will not let loose, and the paper ends up needing to be scraped off the etching plate.
It is important to clean the plate well before inking so that the only thing between the zinc and the pulp is the ink in the lines and grooves of the plate. After the plate has been removed from the dry pulp, it is also important to clean off the ink residue, before reusing the plate. It would seem that corrosion would destroy the imagery on the plate in no time, but it does not if the plate is properly cleaned. The little bit of zinc that is eaten away from the surface has not bothered me; I have printed some plates thirty times.
For a long time I worked with this process not understanding the physics behind it. I thought that only the drying forces of the pulp caused the ink transfer. The corrosion of the etching plate was to me a harmful by-product of the process and, in order to prevent it, I carefully covered the surface of my etching plate with a lacquer, leaving the lines open. Trying to make a print from that plate did not work at all because I had isolated the zinc from the water, preventing the electric current from forming. The actual physical process I eventually figured out with the help of my brother-in-law who is a very good electrician. I have since tried adding 12 volts to the process with a car battery charger, but it made no difference in the end result, only a strange purring sound in the pulp.
This wonderful process allows the printmaker to leave the press and explore 3-dimensional imagery. In 1982 I discovered this technique, but I had very little time to work with it until about half-way through 1985. Most of the work I have described has been done since then. I would like to hear about the results of American and other papermakers or printmakers trying this technique. Please write me.
Peter Gentenaar can be reached at: Sir W. Churchilllaan 1009, 2286AD Rijswijk, Holland. Notes: 1) Cf. Heller, Jules, Papermaking. New York, Watson-Guptill, 1978, pp. 134-5.
