Carbon paper

“ Used in connection with a typewriter of modern construction, the carbon sheet has revolutionized manifolding processes, making possible as many duplicate copies of any paper as are required in ordinary business.
The carbon method of obtaining copies of letters has the merit of economy in time. When the letter is written, the copy is made; if extra copies, up to a half-dozen, are wanted, all are made at one writing. If the last letter is being written when it is time for the mail to leave the office, it need not be held to make a copy. ”

“ In 1874 J. R. Sawyer patented a flexible support for developing on; this was a sized paper coated with gelatin and treated with an ammoniacal solution of shellac in borax, on which wax or resin was rubbed. The advantage of this flexible support is that the dark parts of the picture have no tendency to contract from the lighter parts, which they were apt to do when a metal plate was used, as was the case in Johnson's original process With this patent, and minor improvements made since, carbon-printing has arrived at its present state of perfection. ”

“ In making carbon transparencies for instance, the gelatine film which is squeegeed against the glass necessarily takes its dimensions from the paper to which it is attached, and if that be expanded more in the one direction than another, the transparency is similarly deformed ”

“ INTAGLIO PROCESSES.
PHOTOGRAVURE, AUTOTYPE, DALLASTYPE, ETC.
Photogravure.—First, a photographic negative is taken direct from the picture to be reproduced, and from this an autotype carbon print is taken and transferred on to glass or silvered copper, instead of on the paper used in making carbon prints for sale. This picture is in delicate relief, and forms the mould, upon which copper is electrically deposited. After being made “conductive,” the carbon mould is placed in a galvanic bath, the deposit of copper upon it taking the impression perfectly. ”

“ If such a safe edge be not provided, the carbon print will not adhere to the copper during development; therefore, the extreme edges of the tissue must be guarded from the light during the exposure in the printing frame.
The exposure to light under the negative or transparency must be timed by means of an actinometer, which may be improvised by dividing a strip of tracing paper into ten spaces, and numbering these spaces so:
Write the figures with good black ink and then cut other pieces of white tracing paper into strips of the same width. ”

“ In Swan's carbon process the image is produced in the pigments of the painter, and whatever of permanence may be predicated of a water-color drawing, may be affirmed of the photographs produced in the same materials. If carbon be regarded as the most stable coloring matter which can be employed, lampblack or other similar preparations of carbon can be used in the production of the print. Sepia, bistre, Indian-ink, or any combination of these or other pigments, by which a pleasing monochrome may be produced and permanency attained, is equally available in this method of printing. ”

“ The imperishable nature of carbon, in its various forms of lamp-black, ivory-black, wood-charcoal, and graphite or black lead, holds out much greater promise of being usefully employed in the manufacture of a permanent writing material; since, for this substance, in its elementary condition and at ordinary temperatures, there exists no solvent nor chemical reagent capable of affecting its alteration. ”

“ Those who endeavor to practise it will find it entirely different from the silver process—no gold, no silver, no hyposulphite, entering the construction of a carbon print—yet quite as easy and possessed of many advantages. If what follows should not meet every case, any who may be troubled with failures I shall be glad to answer through the columns of the Philadelphia Photographer, wherein also notes of future experiments, improvements and discoveries in the process shall be regularly recorded. ”

“ Oxygen and nitrogen are free as air, and as we have seen in the second chapter, their direct combination by the electric spark is possible. Hydrogen is free in the form of water but expensive to extricate by means of the electric current. But we need more carbon than anything else and where shall we get that? Bits of crystallized carbon can be picked up in South Africa and elsewhere, but those who can afford to buy them prefer to wear them rather than use them in making synthetic food. Graphite is rare and hard to melt. We must then have recourse to the compounds of carbon. ”

“ It is more difficult to sift out from a large amount of thought and record that which is most important to know—using one's brains as a sieve or filter to separate the good grain from the tares—the sediment from the pure solution, as it were—than to scatter the seed—to distribute the mixture—as one has gathered it from one's own experience and experiment. I have endeavored, however, to compile and write such matter for these pages as will make the novel, fascinating and valuable Carbon Process, plain, practical and easy to all workers in photography. ”

“ It is usually spoken of as pure carbon, but from a very large number of carefully conducted analyses, it would appear that native graphite is never quite pure, even the finest grades of the mineral containing 96·8% of carbon at the most. The accompanying substances—which in some cases186 form nearly 50% of the whole—are of divergent composition and consist of iron, silica, lime, magnesia and alkalis. Even the combustible constituent of graphite is not pure carbon, but always contains a certain—though small—proportion of volatile substances. ”

“ It is not acted on at ordinary temperatures by most reagents, but at a higher temperature it combines directly with many of the elements, forming compounds called carbides. When heated in the presence of sufficient oxygen it burns, forming carbon dioxide.
Uses of carbon. The chief use of amorphous carbon is for fuel to furnish heat and power for all the uses of civilization. An enormous quantity of carbon in the form of the purer coals, coke, and charcoal is used as a reducing agent in the manufacture of the various metals, especially in the metallurgy of iron. ”

“ And again we have shown little willingness to dignify coal by seeking to draw out by improved mechanical processes all the stored content of heat in this lump of carbon. Instead we content ourselves by giving it a mere pauper touch, driving off the greater volume of its value into the air. ”

“ While it is true that carbon in the form of charcoal burns so readily that it is used instead of kindlings for lighting a fire, carbon in the form of graphite in our so-called "lead" pencils and carbon as it is prepared for electric light pencils burns only very slowly even at exceedingly high temperatures. The carbon rods used in arc lamps endure a temperature of over 6000 degrees, without losing more than one inch an hour, and half of that is simply volatilized—not burned. ”

“ In the course of manufacture a process is generally applied to the carbon which is technically termed “treating.” The carbon filament is placed in a vessel surrounded by an atmosphere of hydrocarbon, such as coal gas or vapour of benzol. If current is then passed through the filament the hydrocarbon vapour is decomposed, and carbon is thrown down upon the filament in the form of a lustrous and dense deposit having an appearance like steel when seen under the microscope. ”

“ This gas, previously purified, circulates around the platinum filament, through which an electric current is passed sufficient to bring it to a red heat. This decomposes the gas, and a thin coating of absolutely pure carbon is deposited on the wire. The operation is continued until a sufficient thickness of carbon has been deposited for each type of lamp, and the method of regulating the amount of deposit is effected very simply, and, in fact, almost automatically. ”

“ Carbon possesses a natural power to prevent a limited amount of polarization by absorbing the hydrogen gas coming from the zinc rod; hence it is used in various shapes for open circuit cells, which gives rise to as many different names, such as Samson, Hercules, Law, National, Standard, etc. In all these types of cell, sal-ammoniac and zinc are used, and by corrugating the carbon, fluting it, or making concentric cylinders, special merits are obtained in each case. ”

“ The uses of carbon black are enumerated, and it is alleged that no form of it possessing the same properties and the wide variety of uses can be commercially manufactured from any material or substance other than natural gas. ”

“ To the question, 'Do you consider carbon ink the only permanent ink?' the answers were varied and contradictory. Most of the manufacturers said a carbon ink could not be permanent, because carbon was insoluble; and some said that no chemical union could exist between carbon and the other ingredients in ink. ”

“ Only one-fourth of the earth's surface is land, and perhaps only one-fourth of this land is cropped, and the average crop is about one-fourth of three tons; so that the total present supply of carbon in the air would be sufficient for about two hundred and fifty years. But as a matter of fact the supply is permanently maintained by the carbon cycle. Thus the carbon of coal that is burned in the stove returns to the air in carbon dioxid; and all combustion of coal and wood, grass and weeds, and all other vegetable matter returns carbon to the atmosphere. ”

“ The proofs of organic activity, involving the functions of life, are numerous, but the exact character of that life and the special conditions under which it flourished are greatly if not entirely wanting. In the first place, we find in Canada important, indeed inexhaustible deposits of carbon under the form of graphite, and graphite occurs in our coal measures as the direct product of alteration from coal. ”

“ Other affidavits express the detriment, in the opinion of the affiants, of any restriction or regulation of the production of it; and others, from asserted experts, exhibit the source of the gas and the process of manufacture from it of carbon black, and that in its manufacture heat is necessarily evolved, but that as soon as any attempt is made to transform the heat into any other form of energy, such as light or mechanical power, an enormous, but inevitable, loss of heat results. ”

“ Others claimed that carbon was the one permanent color, and cited the old Indian and Chinese inks which have stood for centuries as illustrations of its permanency. These statements were so widely different that I pursued the inquiry further, and found it was conceded that, if a process could be discovered by which carbon could be dissolved and made to retain its color, no known substance would make so permanent an ink; but that there was no such process, and in the inks now made the carbon was simply held in suspension in the ink without any chemical union ”

“ Not at all; it is very little more difficult than ordinary carbon printing, which is practised successfully by numbers of amateurs. Moreover, such a relief as I have described—which is practically nothing more than an ordinary process block—could be produced by any photo-engraver. The process that I have described is, in all essentials, that which is used in the reproduction of pen-and-ink drawings, and any of the hundreds of workmen who are employed in that industry could make a relief-block of a finger-print, with which an undetectable forgery could be executed. ”

“ In order to ensure a large surface of contact for the terminal of the carbon rod or plate, it is customary to cast a leaden cap on the top thereof; and, as the porosity [Pg 35] of the graphite, or carbon, is very apt to allow the fluid in the battery to creep up to and corrode the terminal, and thus oppose resistance to the passage of electricity, the upper end of the carbon, before the lead cap is cast on, is soaked for some time in melted paraffin wax, at a temperature of 110° Centigrade: that is somewhat hotter than boiling water heat. ”

“ It is an extremely familiar material on the earth; for instance, coal is chiefly composed of carbon. Charcoal when burned leaves only a few ashes. All the substance that has vanished during combustion is carbon; in fact, it is not too much to say that carbon is found abundantly not only in wood, but in almost every form of vegetable matter. The food we eat contains abundant carbon, and it is an important constituent in the building up of our own bodies. Generally speaking, carbon is not found in a pure state—it is associated with other substances. ”

“ If you heat coal or wood away from the air, some gas comes away, and leaves behind coke from coal, and charcoal from wood; both carbon, though not pure. Heat carbon as much as you will in a close vessel, and it does not change in the least; but let the air get to it, and then it burns and flies off in carbonic acid gas. This makes carbon so convenient for fuel. But it is ornamental as well as useful, uncle The diamond is nothing else than carbon. ”

“ Whilst at the present time carbon printing is more largely used by professional photographers, yet its simplicity, the absence of chemical formulæ and complications combined with the beauty of the results, makes it eminently suitable for amateur workers, and hence it has been thought desirable that as an introduction to the subsequent article, a brief and simple outline of the process should be given for the benefit of those who have not hitherto made its acquaintance. ”

“ The crucibles are then heated to a high temperature in an ordinary combustion or electric furnace, whereby the organic matter is destroyed, and a skeleton of carbon remains. The higher the temperature at which this carbonization is conducted, the denser is the resulting product. The filaments so prepared are sorted and measured, and short leading-in wires of platinum are attached to their ends by a carbon cement or by a carbon depositing process, carried out by heating electrically the junction of the carbon and platinum under the surface of a hydrocarbon liquid. ”