ELECTROTYPING
In 1799, Allesandro Volta, of Pavia, in Italy, constructed the first electric battery, which came to be called the Voltaic pile. Improvements in the form of Volta’s battery were made almost immediately by William Cruickshank, in England, who discovered in experimenting with it that he could by its power electrolyze or chemically decompose the salts of certain metals in solution. Both copper and silver, he found, could be precipitated from their salt solutions and deposited upon a plate immersed in the solution.
This observation was the first step in the process of electroplating, which is electrotyping when applied to the art of typography.
In 1837, thirty-eight years after Volta’s discovery, Mr. Thomas Spencer of Liverpool, England, accidentally stumbled upon the first realization of the electrotyping process.
While experimenting with a modification of a Daniell battery, he used an English copper penny as one of the poles instead of a plain piece of copper. A deposition of copper from the solution in the battery took place upon the penny, and upon removing the wire which attached the penny to the zinc plate a portion of the copper deposit was pulled off the penny also.
This first copper electrotype shell Spencer found to be an exact duplicate or mold of part of the head and lettering on the coin. It was as smooth and as sharp as the original.
It was some time later, however, before this suggested to him any useful application of the process. Another accident made him appreciate the full value of his discovery. This time he carelessly dropped some varnish on a strip of copper which he was going to use in the same way he did the penny. Upon removing the copper from the battery he observed that there was no deposition of copper on those parts of the strip where the varnish had dropped.
Spencer then conceived the idea of applying this principle to the arts by coating a piece of copper with varnish or wax and engraving a design in the coating, thus exposing the copper strip in the engraved lines. He did this, and then deposited copper in the design so engraved. Upon removing the coating the design was exposed in relief on the piece of copper.
On September 13, 1839, Spencer read a paper before the Polytechnic Institution of Liverpool, which he accompanied with specimens of both electrotypes made by this process and of printing from these electrotypes. The publication of this paper acted like an electric shock upon society.
Developing his process, Spencer first used lead as the plastic medium in which to mold printing surfaces, and it is to be noted in this connection that in doing so he anticipated Dr. Albert’s lead mold by considerably over three quarters of a century. Spencer impressed a form of type on a planed piece of sheet-lead and subjected both of them to the action of a screw-press. A perfectly sharp mold of the type form was thus made in the lead. This lead mold was placed in a battery, and at the end of eight days a copper shell one eighth of an inch in thickness had been deposited.
It was then removed from the apparatus and the rough edge of the deposited copper filed off. Being subjected to heat, the copper shell loosened from the lead-mold. Spencer called this a “copper stereotype.”
The next step in developing the electrotyping process, after Spencer had demonstrated the practical application of the electro-chemical deposition of a copper shell on a mold, was made by a Mr. Robert Murray. Mr. Murray was the first to use plumbago, or black-lead, to give the surface of non-metallic bodies electro-conductive properties. He discovered that he could coat a mold of bees-wax with black-lead and deposit thereon a copper shell. This was in 1840.
In the same year Smee’s battery was invented. This was a marked improvement and was a most important step towards making electrotyping a commercial possibility.
Thus in 1840, four hundred years after the probable date of the invention of printing from individual movable cast-metal type, and over forty years after the foundation of electrotyping was laid by Volta, electrotyping, as a practical method of reproducing a commercial typographical printing surface, came into existence.
Mr. E. Palmer, in England, using Spencer’s method, was the first to receive a patent for producing a metallic printing plate with the printing surfaces in relief. This patent is dated 1841. Palmer followed this in the succeeding year by a further patent for engraving through a wax-coated matrix-plate to form the printing surfaces in the positive electrotype taken from it. This process was termed by Palmer, “Glyphography.”
The “whites” or low spots in Palmer’s Glyphographs were “built-up” in the wax mold through adding wax by hand, assisted by various ingeniously constructed tools which were heated. After “building-up,” the wax was black-leaded and the copper deposition on the surface of the wax mold was obtained. This copper deposit, or shell, was then tinned on the back, backed up with lead, mounted on wood, and trimmed type-high. These processes are the essentials used today in electrotyping.
One of the earliest works illustrated by the Palmer process is “The History and Antiquities of Brentford, Ealing, and Chiswick,” by T. Faulkner, published in 1845, and the word “Glyphography” occurs at the foot of many illustrations contained in it.
In 1839 the first attempt was made at commercial electrotyping in America. In that year, Joseph A. Adams, a wood-engraver connected with Harper & Bros. in New York, experimented along lines similar to those Spencer had pursued, but using a wood-cut from which to mold. His electrotypes were made by taking an impression from the wood-cut in an alloy of soft metal of which bismuth was probably the chief ingredient, and immersing the metal mold in an ordinary Voltaic battery for the deposition of the copper shell. In making the impression, however, the wood-cut was destroyed so, that this method of making an electrotype was not commercially practical.
The year following Adams took advantage of Smee’s battery and made an electrotype which was used in Mape’s Magazine in 1841. He also employed this process for making illustrations for Harper’s Family Bible, issued between 1842 and 1844.
The first successful commercial electrotyper in America was John W. Wilcox, of Boston. A wood carver named Chandler, told Mr. Wilcox that if he could repeat what Adams of New York had done with a wood-cut in 1839 that he, Chandler, would lend him the necessary wood-cuts for experimental purposes. In less than sixty days in 1846, Mr. Wilcox had put into practical use every essential principle known for the next twenty-five years in electrotyping.
In 1855, Mr. Gay of New York first used tin-foil for the purpose of soldering the copper shells to the metal backing.
During the same year, a Mr. Adams of Brooklyn, New York, invented the dry-brush black-leading machine.
Steven D. Tucker, of New York, developed and patented in 1866 the type of dry-brush black-leading machine which is in common use today.
In 1871, Silas P. Knight, of Harper & Bros., New York, invented the wet black-leading process, and in 1872 took out another patent for an improvement on this process. Mr. Knight’s method of wet black-leading was not generally adopted by the electrotypers of that time and gradually became almost unknown.
Undoubtedly, the cause of this was that the method of dry black-leading was good enough for type and woodcut work. The half-tone had not been invented at that time, and it was only after the invention of the half-tone that a better method of black-leading became necessary.
Thirty-seven years after Mr. Knight had successfully used his process of wet black-leading a patent was granted to Frank L. Learman, of Buffalo, New York, for a wet black-leader. Since that time numerous patents have been taken out on different methods of using the wet process, which is universally recognized today as the best method of graphiting the surface of a mold.
In 1870, Joseph A. Adams patented a process for covering the surface of the mold after it had been black-leaded with powdered tin. This was for the purpose of quickening the deposition of the copper shell when the molds were in the batteries, and from this undoubtedly came the oxidizing process of coating the surface of the molds with chemical copper invented by Silas Knight, which has long been and is now in use.
Perhaps one of the greatest forward steps in the development of electrotyping was made when the plating dynamo was invented. The first adoption of a dynamo in place of Smee’s battery took place in 1872. With the Smee type of battery it required from thirty to forty-eight hours to deposit a copper shell thick enough for commercial use. With the invention of the plating dynamo and its improvements, the time of depositing the shell was reduced so that now two hours is the common time that a mold is kept in the tubs or batteries. This quickening of the time required to deposit the shell was one of the most essential features in the development of commercial electrotyping.
From the first hand-screw presses, which were successfully used for molding, to the modern high-power, motor-driven, hydraulic presses, for working either in wax or lead, is a far cry.
The invention of the half-tone, together with the invention of the modern two-revolution cylinder press which has brought printing into its present state of perfection, made necessary radical improvements in the machinery for making electrotypes. These improvements have been steady in their development, but the fundamental points of the process are practically those which have been in use from the start of commercial electrotyping.
ELECTROTYPING BY
THE WAX MOLD PROCESS
An electrotype is a facsimile printing plate duplicated from an original. The original may be either type, a woodcut, a zinc or a copper etching such as a line-cut or a half-tone, or it may be a combination of type-matter and line-cuts or half-tones.
We commonly think of electrotypes as printing plates made of copper, but any metal which can be electrochemically deposited may be used. Because of their wearing qualities and economy, however, copper and nickel are the two metals commercially used for electrotyping.
Briefly, an electrotype is made by taking an impression of the original in a plastic substance, thus forming a mold or matrix; depositing copper or nickel on the mold; removing the copper or nickel shell from the mold and backing it with a semi-hard metal; trimming the metal to printing-plate thickness, and bevelling, or blocking on wood, the trimmed plate for printing-press use.
In modern practice more than twenty-five different operations are necessary to make a finished electrotype ready for the press. They may be enumerated, as follows:
- Case-making. The flowing of a molding compound composed of “ozokerite,” a resinol-mineral wax, onto the case. The case is of copper.
- Flashing the Case. Passing a flame over the surface of the melted ozokerite immediately after flowing the case in order to remove air- bubbles.
- Case-shaving. The automatic shaving of the top surface of the flowed case after the ozokerite has hardened to give it a smooth, even surface for molding.
- Graphiting. Brushing surface of case with molding graphite to prevent the pattern from sticking to the wax mold.
- Molding. Making an impression from the original zinc line etching, half-tone or type form in the waxed case. This is done by means of a hydraulically operated molding press.
- Cutting-down. The levelling off by hand, using a sharp trowel shaped tool, of the splurge after the impression has been made. Flashing is also used here to remove the burr left around the letters after the cutting down process.
- Building-up. The adding of wax by hand to the blank spaces in the molded case so that in the finished electrotype they will be well below the printing face.
- Black-leading. Making the face of the molded case electrically conductive by applying graphite.
- Stopping-out. Insulating with a thin coating of wax the edges and back of the copper case to prevent copper being deposited except on the face of the mold.
- Pumping-out or Oxidizing. Coating the face of the molded case with chemical copper to hasten deposition of copper shell in the bath.
- Deposition of Shell. The molded case is put in the electrolytic bath for the deposition of shell thereon.
- Releasing Shell from Molds. Stripping the deposited shell from the waxed mold by dashing hot water on it. The wax is melted off case and used again.
- Washing Copper Shell. Hot lye-water or steam is used to clean off any wax sticking to it.
- Trimming Copper Shell. Rough edges of shell outside the guard line trimmed off.
- Aciding Copper Shell. An application of fluxing medium to back of copper shell so that tin will adhere.
- Tinning Copper Shell. Tin- foil is melted on the back of the copper shell. This is the solder between the copper shell and the metal back, without which the metal backing would not adhere to the shell.
- Backing-up. The flowing of electrotype metal on the back of the tinned copper shell for the purpose of making a foundation for printing (electrotype metal is an alloy of 94 per cent lead; 3 per cent tin for flowing and 3 per cent antimony for hardness).
- Scrubbing the Cast. A power operated scrubbing machine using a hydro-carbon oil as the cleansing medium to clean the printing face of the electrotypes.
- Cast-sawing. Sawing off the surplus metal of the cast before finishing.
- Flattening the Casts. Hand operation with mallet and flattening block to take the warp out of the electrotype caused by the contraction of the metal in cooling.
- Rough-shaving. Planing off superfluous metal from the back of the electrotype.
- Finishing. Putting the printing surface of the electrotype in perfect condition for press after leaving the foundry department. This is done by hand and requires a high degree of skill.
- Smooth-shaving. The finishing shave of metal from back of electrotype to bring it to the required thickness.
- Routing. Cutting out the high but non-printing surfaces of the electrotype by a routing machine.
- Guard-line Sawing. Cutting the guard lines or bearers off the electrotype to practically the finished size before blocking or bevelling.
- Blocking. Fastening the plate on wood base with brads driven through the metal.
- Trimming. Trimming the wood mounted electrotype to its exact finished size.
- Type-high Machining. Used for planing the bottom of the wood base so that the mounted electrotype is of printing press requirements, i. e., .918″ high.
ELECTROTYPING BY
THE LEAD MOLD PROCESS
Electrotypes made by the genuine Dr. Albert Lead Mold Process are always duplicates of fine-screen half-tones or mezzo-tints used for the highest class of commercial job-work, such as three and four color process or duo-tone printing on paper with a highly glazed surface.
The largest press used in lead molding will give a maximum pressure of two thousand tons per square inch on a thirty inch ram hydraulically operated. The weight of this press is over thirty thousand pounds.
In the lead mold process the plastic medium used is a soft thin sheet of what is called “impression lead,” .040 inches thick, instead of wax, and the lead is placed on top of the original to be duplicated, instead of vice-versa, as in the wax-molding process. No “building-up” nor “black-leading” is necessary.
In all other respects the consecutive steps towards the completion of the lead mold plate are identical to those used in the Wax Mold Process.