A technical dictionary of printmaking, André Béguin.
1. COMPLETE DEPOSITING GALVANIC PROCESSES.
The idea of covering or plating an object to protect it or to make it more attractive existed already in antiquity. Gold and silverplating processes were already practiced by the Greeks and Romans by means that were not exclusively manual since Pliny the Elder spoke of a goldplating process using mercury which is still in use today. However, the covering of printing blocks was not done until the discovery of electrolysis.
Already in 1803 Brugnatelli had observed that one could goldplate with a pile (battery) and an alkaline solution of gold. The application of this observation was carried out by Rive who used piles to do both silver and goldplating. However, it was not until 1838 that the Russian physicist H. Jacobi was able to obtain a relief block of a cast made from an intaglio copper plate an invention he then presented to the St. Petersburgh Academy of Sciences. The Englishman Spencer made the same discovery which was perfected by Elkington and the Frenchman Ruolz one year later. In 1840, working separately, Buckland and Bocquillon each reproduced printing blocks using a galvanic process. In 1842 Böttger showed that it was possible to obtain nickel plating using as an electrolyte a solution of nickel ammonia.
As of 1845 electrolytic plating, electrolysis, became an industrial process in part due to Wood's discovery of the conductivity of graphite. In fact, graphite was to be adopted to "metallize" non-conductive but light materials such as wax, guttapercha, and, later on, plastics.
In 1847 Gamier and Salmon applied electroplating (also called galvanoplasty) to protect engraved copper plates. The steelfacing they had invented protected the relatively fragile copper plates from deteriorating too rapidly when printed.
After the revolution of 1848 the French government had to issue post-haste 100 franc bills. The printer Firmin Didot was commissioned and, thanks to electrolytic processes, was able to reproduce the plates of the old bills as well as to make copies of the plates so obtained. Thanks to these copies the printing of the bills resumed as of 1851. In 1849 Hulot had managed to make plates on which he had reproduced the same image no less than 300 times. In 1855 Michel used a galvanic process to reproduce a page of text. Electroplating (galvanoplasty) was also used to reproduce vignettes and ornaments, from wood blocks, which could be printed typographically. Such reproductions spared the delicate and expensive originals. The Englishman Cole restored some of Dürer's blocks, took moulds of them, and made metal plates from which new runs of Dürer's work were printed.
A complete depositing on a plate results in a homogenous and regular plating of the obiect if the work is carried out properly. The thickness of the depositing is determined by the amount of time the current is turned on [electrotyping].
Above and beyond making plates by using electrotyping in conjunction with relief typographical composition there are various processes using complete depositing. In fact it is possible to copy an intaglio plate (sometimes quite a shallow one) and make a relief block for typographical printing or, less frequently, to make an intaglio plate from another intaglio plate or from a relief block. Usually electroplating serves to transform a weak plate into a solid one suitable for printing.
THE LEVRET and DELFRANCE PROCESS. In this process drawing is done on
tracing paper which is later backed with 1/4mm (0.10in) of gelatine, applied in
several layers. The composition of this solution is as follows:
water ...................1000 g
gelatine ..................50 g
glycerine ..................5 g
As the drawing can be seen in transparency one can engrave the gelatine layers.
When the engraving is done it is covered (the gelatine side, of course) with a solution of guttapercha dissolved in carbon disulphide (the proportions being one to two). The solution is applied with a brush in 30 superimposed layers, waiting for each to dry before applying the next. The paper and the gelatine are then removed with hot water. The resulting "cast" is then sprayed with some graphite and is plunged into the electroplating bath as is explained in the article on electrotyping.
THE FERGUSON BRANSON PROCESS or SOAP PROCESS. The engraving is done on a plate made of soap (preferably containing vaseline) that is 3cm thick (1.2 in). The engraving, which is easily cut due to the material used, is then used to make a mould with fine plaster, with guttapercha, or with wax and is then "metallized". The metallizing can be done with the soap itself using 2% copper sulphate or some powdered zinc or silver. One of Rembrandt's etchings was reproduced using this process.
THE WAX PROCESS. Same procedure as above but carried out on wax melted into
a frame 2cm (.8in) high. The wax used is made up of:
yellow wax ..............25 g
paraffin .................25 g
plant wax ................40 g
graphite ................. 3 g
fine copper sulphate ..... 7 g
or white lead ............50 g
graphite ................. 5 g
HOT POINT WAX PROCESS. The engraving in this process is done using a hot point on a plate made of: 8Og paraffin and 2og mineral wax.
"GYPSOGRAVURE" (Michaud patent of 1882). The plate is made using fine plaster which is then hardened with potassium silicate and made impermeable with a gelatine solution. The plate is then engraved (photographic and lithographic transfers can be made). The metallizing is done with graphite or silver sulphide.
RUBBER PROCESS or SEELY PROCESS. A sheet of rubber that has been cleaned properly is exposed below an inversed negative and is then plunged in benzine. The parts of the rubber that were not exposed swell up and create a relief design. The rubber plate can be shaded by using a screen during exposure [ phototype].
CELLULOID PROCESS. The same procedure as above but done on celluloid plates.
SCHOELER, PALMER, DARFIL PROCESS. The same procedure as above but done
on a plastic plate whose composition is as follows:
lamp black............ 5 g
spermaceti............ 8 g
lamp black............ 2 g
white lead............25 g
danor gum.............25 g
lamp black............ 5 g
The preparation is then covered with silver white which makes the lines show up black during engraving. The results of this process are very precise indeed.
All of these processes differ from each other in the preparation of the engraving itself but the final electrolytic process is the same for all. This is not the case in the following processes all of which are selective ones.
2. SELECTIVE DEPOSITING GALVANIC PROCESSES.
Selective depositing is somewhat like etching the difference being that the combinations allowed for by these galvanic processes are manyfold. It is possible to obtain a wide range of results by depositing different metals one on top of the other, metals which react in different ways to an acid or that stick to the plate in different ways.
A. ELECTROLYSIS USED FOR DEPOSITING.
THE PALMER, AHNER, WALKER PROCESS (GLYPHOGRAPHY). A copper plate is covered first with a black ground and then with a white one. The drawing exposes the plate surface which is then metallized with graphite. The depositing turns the plate into a relief plate. To accentuate the relief a plaster cast can be used as a shell.
THE FIRMIN DIDOT PROCESS. This process has much in common with the previous one. The starting point is, however, an etching which has just been bitten and from which the ground has not yet been removed. The etched parts of the plate are inked several times over with a quick drying ink. The same areas are then given some graphite. This process allows for an etching to be copied for typographical printing.
BESLAY PROCESS. Plate glass is covered with an etching ground to which graphite or powdered copper sulphide has been added. After engraving the plate is put into the depositing bath. As the depositing takes place only on the areas that are not engraved the result will be a relief plate.
GALVANOGRAPHY ( Kobell process, 1840). Similar to the preceding process. The drawing is either done with an encaustic ink (made up of 30g wax, 30g lamp black, and 30g turpentine oil) or with a lithographic crayon. The drawing is done on a silverplated copper plate which has been previously been grained in much the same way as an aquatint plate. The areas that are not drawn on are those that will be in relief.
THE DUMONT PROCESS ( 1854 ) The drawing is made with a crayon or lithographic ink on a grained zinc plate. After the drawing is completed the plate is heated and powdered with resin so as to be better isolated. The plate is then plunged into a bath of zinc sulphate (the plate being on the negative pole). The result is a relief design from which a mould can be made.
TRANSFER ELECTROTYPING. This process transforms letterpress or lithography work into an intaglio plate. To begin with an impression is made with autographic paper (using autographic ink) and then this is transferred unto a copper or zinc plate. The inked parts are then dusted with resin and the plate is heated so that the resin dust will stick to the metal. The depositing is then carried out and the precipitate will settle onto the areas that are not inked.
THE DULOS PROCESS. A copper plate is drawn on using lithographic ink or crayon. The
plate is then silverplated and the silver settles only on the areas that are not
inked. The crayon marks or the ink are removed with gasoline leaving a copper
drawing which is heated in order to oxydize it. The next step is to apply a silver
amalgam (mercury plus silver) with a roller. This amalgam will catch only on the
silverplated areas, thus making the drawing become an intaglio image. This intaglio
image is then used to make a mould and the mould is, in turn, used to make a block
for typographical printing.
One can also, after having done the drawing, deposit iron onto the areas that are not drawn upon which is then followed up by silverplating (after cleaning the crayon or ink drawing). The next step is to remove the iron deposit using weak sulphuric acid as a mordant, thus turning the plate (the drawing, to be more precise) into a relief. One can then further raise the design by applying the silver amalgam again with a roller.
A variant of this process consists in working a copper plate through a ground made of rubber and zinc white. The areas of the plate exposed by this drawing are covered with an iron deposit. In order to obtain an intaglio plate the ground is removed and the plate is silverplated. The silver will only catch on the copper, that is, on the areas that were not drawn upon. The iron is then bitten using a weak concentration of sulphuric acid and, as mentioned above, the silverplated areas can be raised with amalgam. In order to obtain a relief drawing all that has to be done is to make the first deposit be silver instead of iron. One can also raise the copper areas of a plate, without having recourse to silverplating, by using a special copper amalgam.
The Conite process is much the same as the one just described.
THE LYONS AND MILWARD PROCESS. This process is also much like the preceding
one. Relief or intaglio plates are obtained by means of selective superimpositions
of different metals achieved using grounds, the incompatibility of metals, and with
chemical etchings. While on the subject of incompatibilities, the reader should be
reminded that iron, steel, and cast iron will take goldplating, silverplating and
nickel-plating while bronze, brass, copper, cast iron, and iron will take silverplating.
Iron, steel, and copper will take zinc plating (galvanization) while copper wilt
take iron plating and zinc, lead and brass will only take copper plating.
The Lyons and Muward process was above all used to make rotary plates for printing on cloth.
THE LEPIERRE PROCESS. This process consists in taking a sulphur impression of a greasy ink design. The sulphur is poured directly onto the drawing and, after drying, any traces of paper are removed, if necessary by brushing the sulphur with a brush. If the paper is not removed the original impression is damaged if not totally lost. The greasy ink sticks to the sulphur and becomes quite indelible. If the sulphur is then metallized it is quite simple to make a plate using a depositing (plating) procedure.
COBLENCE PROCESS. The drawing is done on a polished zinc plate using an
asphaltum ink diluted with oil of
turpentine. The plate is then slightly etched with a 10%
nitric acid solution so as to obtain a
slight grain [
biting]. After cleaning off the ink apply another layer of the same
asphaltum ink onto the plate. This second layer of ink will only be caught by the
grain. The depositing bath is made with
potassium cyanide and copper.
Only the areas of the plate having a brilliant finish wilt receive the deposit.
The plate is then washed with gasoline followed by water and brushed clean. The next
step is to etch the zinc areas in order to raise the drawn area which, after the
depositing, is covered with copper. The etching solution is made of 1000g of water,
200g of nitric acid, lOOg of sulphuric acid, 400 g of
copper sulphate, 400 g of
iron sulphate. The etching must be
carried out for some two minutes.
The resulting plate can be used for hand impressions of negative intaglio. Insofar as concerns typographical printing, it will be necessary to etch the zinc again after inking the relief areas. The plate must then be copper plated and steelfaced for printing.
B. ELECTROLYSIS USED AS A MORDANT.
GALVANOGRAPHY (Jacquemin process). The first step is to draw with lithographic ink dissolved in albumin and water. When the drawing is finished the ink is heated to 100°C (212°F) which coagulates the albumin and makes the ink insoluble. The plate is then connected up to the positive pole in an electrolytic bath. The depositing takes place on the negative pole and removes metal from the plate. Due to this phenomenon the plate is "etched" in the areas that do not carry the drawing.
ZINCOGRAPHY (Devincenzi process). The drawing in this process is done on a zinc plate that has been prepared as if for lithographic work, which means that the plate is scoured and drawn on with chemical ink. The drawing is then rubbed with a decoction of oak-gall followed up with gum arabic. The plate is then washed with water and the ink is removed with turpentine oil. After drying, the plate is dampened and then grounded (using a roller) with a mixture of asphaltum, litharged linseed oil, and turpentine to which one adds a bit of lavender oil. This ground catches only on the drawn areas of the plate. The plate must dry for twelve hours. When the drying is completed the plate must be covered with a weak solution of sulphuric acid in order to clean it. The next step is to plunge the plate into a dissolution of copper sulphate at 15°C (59°F). A copper plate of the same dimensions must be placed parallel to it 5mm (0.2in) away. During electrolysis the copper plate must be connected to the zinc plate with a little copper rod. The areas of the zinc plate that were not drawn on are etched both by the copper sulphate solution and by the electrolytic process underway. The zinc plate is removed every minute to remove the copper that is deposited. In four to eight minutes there will be sufficient relief for typographical printing.
ELECTRO-ETCH (Omri Behr)is a new, patented, ecologically safe way of etching an image into a metal plate without using acid. The plate is covered with a resist and portions of the resist removed to create an image. The Electroetch processor consists of a tank filled with a conducting solution, a plate of the same metal as the image plate, and a source of low voltage DC electricity. The image plate is put in the tank, the positive pole of the power source connected to it and the negative pole to the other plate. When current is passed, the electricity etches the image by moving the exposed metal to the other plate. The etched image plate is removed from the tank, cleaned, inked and printed in the traditional way.electro-etch
Drawing, depositing (plating), and etching is always done after a thorough
scouring of the plate.
When resin is powdered onto the plate it must be done from a certain height in a draft-free room. The powder that is not meant to stay on the plate can be quite simply blown away. The reader may have noticed that there are two different processes which are called galvanography, one being a depositing process while the other is an "etching" process. The same problem arises in the case of the electroplating process called zincography which must not be confused with the lithographic process and the gillotype process which, at times, are also called zincography.