Part 9

Illustration: STAMPING THE PEN FROM THE STEEL.

Illustration: BENDING THE PEN.

Steel pens, which have almost superseded quill pens, are made in great quantities, and, like needles and pins, can only be produced at a sufficiently low price to meet the requirements of the people, by those who have erected buildings and fitted up machinery so as to make the process sufficiently rapid to be cheap. The steel is first selected of the proper quality, and rolled out into sheets of the thickness required and of breadth sufficient for the length of the pens to be made; these are punched out of the proper shape by a punch worked by a screw, which cuts out a piece at every blow, and also the perforation which terminates the split. The maker’s name or any other device is stamped on this flat piece of steel, called a “blank,” which is then coiled up into the shape required (whether a “barrel” pen or a “nib”) by a sort of press, worked by a girl, as seen in the engraving, and the split made by a machine, also engraved. In both these machines the screw is worked with the left hand, while the right is engaged in placing the pens under it and pushing out the pen with the finger after it is bent or slit, these operations, from constant practice, being performed with great rapidity. The pens have next to be tempered, by being made red-hot and then thrown into water or oil, and are afterwards polished by putting them into a barrel with fine sand, which is turned round by a windlass for several hours. The nibs or points are then finished at a stone which turns round, and a varnish of a brown color--made by dissolving shellac and asphaltum in naptha--is given to the surface to keep them from rusting. Sometimes the surface is “blued,” which is done by heating the pens on an iron plate till the blue color appears (see “Steel”).

Pens are sometimes made of other metals besides steel, as brass, or zinc, and sometimes of gold. Those made of gold are, of course, too expensive for general use, but as they are never corroded by the ink, they last a very long time, and can always be cleaned by washing; and as the whole wear is at the point, this is tipped with an alloy which is exceedingly hard.

ARTS AND TRADE PROCESSES.

WOOD AND PLATE ENGRAVING.

Illustration: WOOD ENGRAVING.

Engraving consists principally of two kinds, that in which the design is made to project, and that in which it is cut in or indented; the first kind is used in wood engraving, and in engraving metallic or wooden blocks and cylinders for calico printing, the other is called “plate engraving,” and is used to produce copper, steel, and zinc plates for printing.

In wood engraving a block of box wood is used, or several pieces are screwed or tongued together in order to make a block of the required size, for the box wood must be cut across the grain, therefore large blocks are not easily procured. These blocks are about an inch in thickness, so that they may range with type and be printed with it, they are made perfectly smooth on the face, which is rubbed with a little flake-white and Bath brick, to give it a whitish and slightly roughened surface. On this prepared surface the design is drawn with a black-lead pencil, and the block is then put into the hands of the engraver, who cuts away--to the depth of about one-twentieth of an inch--all those parts which have not been blackened by the pencil, leaving every line and dot of the drawing projecting, and this serves as a sort of stamp or type, to print from. (See “Printing.”) In this way the illustrations to the present work are produced.

In plate engraving the design is copied from the original and cut into the plate in a manner quite opposite to that of engraving on wood; for every line intended to be printed, instead of projecting, is cut in with a sharp edge, so that they may be filled with ink, instead of being covered, as in wood engraving. When the design is formed entirely by lines, it is called “line engraving,” and when formed by dots, it is said to be “stippled,” and these two kinds are often combined in the same plate. There is a process for engraving plates, called “etching,” by which the lines or dots on the plate are not made by cutting, but are corroded or eaten in by the chemical action of nitric acid; and few plates are now produced by the graver alone, the design being first etched and afterwards finished off by the graver, but some are produced by etching alone, whence they are called “etchings.” The process of etching is as follows:--The surface of the plate is made smooth and bright, then heated, and afterwards coated with a mixture of asphaltum, wax, and mastic--called “etching-ground”--a ball of which is tied up in a piece of silk, rubbed over the hot plate, and dabbed with a dabber till a smooth layer or coating is formed all over it; it is “smoked” over the flame of a candle, to blacken it, and the result is a smooth black varnish, which covers the surface of the plate, and is capable of resisting the action of nitric acid. On this surface the design is drawn with an “etching-point,” a steel instrument which cuts or scratches quite through the etching-ground, exposing the surface of the copper at the bottom of each scratch. When the design is finished--in hues or dots, according to the style required--a ridge or border of wax is made all round the plate so as to form it into a sort of shallow tray, and into this the nitric acid, mixed with a little water, is poured, and carefully watched till in the judgment of the engraver it has bitten into the plate sufficiently for the fainter parts of the design. The acid is then poured off, and the plate washed and dried, after which the parts intended to remain most lightly etched are stopped out with varnish, and the acid again poured on, to corrode the lines left exposed to its action more deeply. This is repeated two or three times, according to the nature of the design, when the plate is again heated, to melt the etching-ground, and the whole is cleaned off with turpentine. The plate may now be used to print from, or it may be further finished by the “graver,” “burnisher,” or “dry point,” which is simply a point of steel used to make very fine and faint scratches instead of cuts, for the graver cuts out the piece of copper, while the dry point merely indents it.

There is another kind of plate engraving, called “mezzo-tinto.” This is done by first covering the whole plate with a rough granulated surface--called a “mezzo-tint ground,”--by means of a sort of notched chisel, called a “cradle” or “grounding-tool,” which is rocked to and fro over the surface in every possible direction, till the whole is covered with minute dots; so that if it were then used to print from, it would produce an even dark surface. On this ground the engraver works with a “scraper,” scraping gradually away all those parts which are to appear as lights in the finished picture, and the more the ground is scraped away the lighter will be the tint, till, finally, those parts which are to be quite white are scraped smooth and burnished, so that they shall hold no ink at all. In this way the engraver proceeds till his design is finished, trying the effect from time to time. This kind of engraving is often combined with etching, producing greater sharpness of outline than mezzo-tint alone.

LITHOGRAPHY.

Illustration: LITHOGRAPHIC PRESS.

This is the art of producing designs upon stone in such a manner that impressions may be printed from them. It is often miscalled “engraving on stone;” properly speaking, it is not engraving, but a process depending on the want of affinity between watery and greasy matters, the design being made with a greasy substance, either in the form of ink or crayon called “lithographic chalk,” as follows. A close-grained stone called lithographic stone (a kind of magnesian limestone) is ground perfectly even on the surface, and (if for being written upon) polished with pumice-stone, or (if for being drawn upon with chalk) grained with fine sand; the design is drawn with chalk or ink, each of which is made up of greasy materials--wax, soap, and asphaltum, colored with lamp-black. When the design is made, the stone is etched--washed over with a weak mixture of nitric acid and water--which answers three purposes; it very slightly bites away the stone in all places except where it is covered with the ink or chalk, it smoothes the grain in the same places, and it converts the soap of the ink or chalk into grease. We have now the surface of the stone quite wet, except where the design is, which, being greasy, keeps quite dry. The stone, placed in a press, is rolled over with a roller smeared with greasy printing ink, which will not adhere to the wet stone, but it readily does to all parts of the design; a piece of paper is placed over the stone, and a flap of leather covers it; along this leather the scraper of the press is brought very forcibly when it is worked, and on removing the paper an impression is found to be transferred to it from the stone. This process is repeated again and again, many hundred times, without much injury to the original design.

Colored lithography, called chromo-lithography, is produced by using several stones consecutively (each transferring a separate color), so that the design shall be complete when the whole are printed.

PRINTING.

The art of printing consists in producing impressions from a pattern or types--cut out and projecting, or engraved and indented--by smearing the projecting parts or filling up the indented markings with ink, so that impressions, to any number, and exactly resembling each other, may be taken from them. Printing is comparatively a modern invention, although impressing or taking impressions from seals is one of the very oldest. It is divided into two kinds, plate-printing and surface-printing. Printing from type or blocks having the marks to be impressed raised, is called surface-printing, while that in which the lines or marks are cut in, is called plate-printing.

Illustration: PRINTING-PRESS.

Illustration: INKING-TABLE.

In surface-printing, when types are used, they are packed up closely into masses and wedged together in iron frames, so that they form, as it were, solid blocks; the types or wood-blocks when required to be printed from are placed in the press, and rolled over by a roller smeared with printing-ink--this roller is coated with an elastic substance made of glue and treacle, and resembling India-rubber. It is worked to and fro on the “inking-table” (a smooth iron slab fitted with a receptacle for ink), in order that the ink may be evenly distributed over its surface--a point to which great care and attention, and no little skill, on the part of the workman, is directed. The ink, being rolled over the type, covers and adheres to the surface of the projecting parts. The paper is placed on a frame turning upon a hinge, and is secured in its place by another frame brought down upon it. These frames, with the paper, are now turned down upon the blackened surface of the type, and the whole--paper and type--passed under the printing press, where, by the working of a handle, a piece of iron is caused to descend and press evenly and with great force upon them. On being withdrawn, and the frames opened, the paper is found to have received a perfect impression, in ink, of the type upon which it was impressed. This process, of course, can be repeated to any extent, and as many impressions produced as may be required.

In plate-printing, the plate is first warmed, and all the engraved parts are filled in with ink, the superfluous ink being wiped off, and the surface cleaned bright by using a little whiting (which is rubbed on the hands), leaving only the indented parts full of ink. The paper (in a damp state) is then laid on the plate, with a fold or two of flannel over it, and the whole is carried, by turning the handles of the press, between two rollers, which compress the plate and paper together so forcibly that, when removed, the ink is found to have left the plate and attached itself to the paper, forming an impression.

Printing is now in very many cases done by machinery, worked by steam power, so that a very large number of impressions can be produced in a very short time, as in the case of newspapers, the whole impression of which (amounting to many thousands) is printed in a few hours.

Printing in colors of various tints, so arranged as to form a picture, has lately been much resorted to. The usual method pursued is to print one color, and when that is dry, to print the next, and so on till the picture is complete; but a machine has been invented by which many colors may be printed at one time.

PHOTOGRAPHY.

Illustration: CAMERA FOR STEREOSCOPIC PICTURES.

Illustration: FIG. 1. (‡ REDUCED VIEWER IMAGE.)

Illustration: FIG. 2. (‡ LENS ARRANGEMENT.)

Illustration: FIG. 3. (‡ IMAGE TRANSFERENCE.)

The principle of this art depends upon the property which certain chemical preparations (chiefly those of silver) possess of being blackened by exposure to light while in contact with organic matter, and that in so gradual a manner that every degree of shade may be represented. Now, as the various appearances of everything we see depend upon the effects of light and shadow (together with the peculiar color of the objects themselves), it follows that if these lights and shadows can be transcribed, we shall have a representation of the objects, minus their own proper colors--and this is what photography effects. For the purpose of bringing the objects to be taken within a small compass, and for increasing their vividness, an instrument is used called a camera, in which there is an achromatic arrangement of lenses (shown in figs. 2 and 3), which produces a picture on the paper or glass to be affected by the light, in the same way that a common magnifying glass will, if held at a proper distance from a piece of paper, but much more perfectly (fig. 1). The effect of this camera-picture on the paper or glass when properly prepared and subjected to its influence, is to darken the paper in all those parts which in the camera-picture are the brightest, and to leave unaffected those parts which are the darkest, thus producing what is called a “negative picture,” having the lights represented by shadows and the shadows by lights. This is used to form the true or “positive” picture, which is done by placing the negative on a piece of prepared paper, and exposing it to the light. The negative having been made partly transparent by wax (as will be further explained), and the parts of the picture which are to be dark being left transparent, the light passes through them and blackens those parts of the prepared paper behind, while those which are to be light, being dark in the negative, exclude the light and thus preserve the paper at the back from being darkened; the paper is thus affected in the contrary way to the negative, and is therefore a true picture of the lights and shadows of the object copied. This is the principle of all photographic pictures, but with numberless variations in its practice; it would therefore be impossible here to describe the particulars of each process, beyond the most simple.

Illustration: FIG. 4. (‡ PHOTOGRAPHIC PLATE.)

Perhaps of all the various arts discovered by man, this is the most beautiful, producing a perfect likeness of any being or object in a few moments, and with a truth not to be equalled by years of study and practice in other ways. One of the earliest discovered and simplest modes of forming a sun picture consists in using the object itself (where this is possible) to form the negative. This can only be done when the object is flat, as a manuscript, a picture, a leaf, or a piece of lace-work; a piece of paper washed over with a solution of common salt, dried, and again washed over with a solution of nitrate of silver, will answer for this purpose; it should be prepared by candle-light, as daylight blackens it, and it should be kept from the light till the moment for use. If this paper, having the object to be copied placed on it and kept flat by a piece of glass pressed firmly on by a contrivance shown in fig. 4, be exposed to the sunshine, it will be blackened in all places but those kept from the light by the darker parts of the object, and the lights and shadows will vary accordingly as the various parts of the object itself are more or less transparent. When the effect has been produced to a sufficient degree, the paper should be removed and at once washed in a solution of hyposulphite of soda, which removes all the superfluous silver (which otherwise would be darkened by the light); when removed from the hyposulphite of soda it should be well soaked in clean water. This when finished is a true negative picture of the object, and can be used to produce the positive. The negative should first be made partly transparent by brushing it over with some melted white wax, then placing it between folds of blotting paper and passing a hot iron over it, the blotting paper will absorb all the superfluous wax, and the negative will be fit for use. A piece of paper prepared like the first with salt and nitrate of silver, should be placed against the front of the negative, kept smooth by a piece of glass, and exposed to the sunshine for a quarter of an hour or more, taking care that the back of the negative is exposed to the light and the prepared paper behind; a positive picture will be produced, which is to be at once treated with a solution of hyposulphite of soda and washed with clean water, as was the negative. Any number of positive impressions may thus be produced.

The “Calotype” or “Talbotype” process may be performed as follows, recollecting that all these processes must be conducted by candlelight, or in a room having the window covered with yellow silk, or some other substance excluding white light. Select a piece of paper of an even surface and structure, such as Whatman’s paper, brush it over with a solution of nitrate of silver--about sixteen grains to an ounce of water--and let it dry, then fold up the edge of the paper all round and dip the surface to which the solution of nitrate of silver has been applied into a solution of iodide of potassium--an ounce to a pint of water--contained in a shallow vessel, and let it partly dry; float it for a quarter of an hour in a vessel of clean water, moving it gently about so as to remove all soluble matter, and hang it up by a corner to dry, taking care to let nothing touch the surface. When about to be used, this paper must be brushed over (using a soft camel-hair brush) with a mixture, in equal quantities, of a solution of nitrate of silver--fifty grains to an ounce of water--and a saturated solution of gallic acid, forming what is called the “gallo-nitrate” of silver. Leave this solution on the surface for ten minutes, and again immerse the paper in two or three successive portions of pure water, moving it to and fro; this, when nearly dry, is in a fit state to place in the camera, and is an exceedingly sensitive paper, which in a good light will be affected in a few seconds. When the image has been impressed by the camera, the paper should again be brushed over with the gallo-nitrate of silver, and held either near a fire or a plate of hot iron, so as to receive a gentle warmth; the impression will now come out, of a deep rich colour. Dip it into warm water for a few minutes, and put it into the hyposulphite of soda bath--an ounce to a quart of water--from which it is finally removed and placed in a large vessel of pure water for several hours. When dry, it is complete, forming a good negative, which, when waxed, may be used to print positives as before described.

The “Collodion” process is conducted as follows. Having selected a plate of glass of the required size and of good quality (patent plate answers well), clean it thoroughly with rottenstone and spirits of wine, and polish it with a clean dry linen cloth; then hold it on the tips of the fingers and thumb in a horizontal position, pour upon it a small quantity of the “iodized collodion,” and so incline it from side to side, that all the surface shall be covered with the collodion, that which is superfluous being returned to the bottle by pouring it from one corner of the glass. In a few minutes the coating of collodion will be dry, and should form a perfectly even surface, without air spots or uneven markings. The iodized collodion is made by dissolving gun-cotton in ether, and adding spirit of wine and iodide of ammonia. The glass plate coated with collodion is now dipped into a solution of nitrate of silver--thirty grains to an ounce of water--and allowed to remain two or three minutes; when all the superfluous fluid has drained off, the plate is ready for use, and is extremely sensitive to light. When the impression has been produced by the camera, a solution of pyro-gallic acid, mixed with a little acetic acid, is poured over the surface, which brings up the image; when this is developed to a proper extent, the surface must be washed with clean water and afterwards with a solution of hyposulphite of soda, which dissolves out all the silver from those parts not darkened by the light in the camera, leaving the glass in those parts quite transparent. A negative is thus obtained fit to print from in the usual way, but glass being more transparent than the waxed paper, it produces a more perfect positive. The surface thus prepared should be coated with a varnish, made by dissolving amber in chloroform, which is done by pouring it on and decanting the superfluous varnish similarly to the mode of coating with collodion; this varnish dries in a few minutes, and preserves the surface from injury. Sometimes these negatives are converted into positives, instead of being used to print from; in these cases the surface is coated with black japan, and the collodion, having a whitish surface, owing to reduced silver, shows up in comparison with the black varnish which is seen through the transparent parts. These positives are extremely sharp and well defined.

The “Daguerreotype” process consists in forming the image on the surface of a metallic plate (copper coated with silver), which is first polished to a perfect surface like a looking-glass, then exposed to the vapour of iodine in a properly-constructed box, afterwards to the vapour of chloride of bromine, and again to the vapour of iodine; this produces a thin film of a mixture of bromide and iodide of silver, which covers the surface of the plate, and is very sensitive to light, which reduces the iodide and bromide to the metallic state in a few seconds. The plate is then exposed to the action of the light in the camera, and when sufficiently affected, exposed to the vapour of mercury, the mercury being put into a box, and heated by a spirit lamp; the mercurial vapour adheres to all the parts of the silver reduced by the light, and forms a light-coloured amalgam, corresponding to the lights of the objects represented. The plate is then washed with a solution of hyposulphite of soda, which removes all the bromide and iodide of silver not reduced by the light, and exposes the highly-polished surface of the silver, which forms the shadows of the picture; this is now “fixed” with a very weak solution of chloride of gold and hyposulphite of soda, which is poured over the surface and heated while there by applying the flame of the spirit lamp to the back of the plate for a minute or two; the solution is then poured off, and the picture when washed with water is complete.

ILLUSTRATION: FIG. 5. (‡ STEREOSCOPE.)

Illustration: FIG. 6. (‡ STEREOSCOPIC SLIDE BOX.)