Part 3

The metal plate, of copper or zinc, is coated with a very thin layer of bitumen of Judæa, and when this coat has become perfectly dry, a film of bichromatized albumen is flowed over the plate. It is next exposed in the camera, and afterwards washed with water, in order to dissolve all the albumen which has not been rendered insoluble by the luminous action; it is then treated with spirit of turpentine, which dissolves all those parts of the layer of bitumen that have become exposed. The plate can now be attacked directly by water acidulated with from four to six per cent of nitric acid. The great advantage of this method consists in the high sensitiveness of the bichromatized albumen, at the same time preserving the solid reserve produced by the bitumen of Judæa on a metallic surface.

TO MAKE NEW A CORRODED PEN.

When a pen has become so corroded as to be useless, it can be made good as new by holding it in the flame of a gas jet for half a minute; then drop in cold water, take out, wipe clean, and it will be ready for use again.

ENAMEL FOR FINE CARDS.

For the brilliant enamel now often generally applied to fine cards and other purposes, the following formula is given:--For white and for all pale and delicate shades, take twenty-four parts, by weight, of paraffine; add thereto 100 parts of pure kaolin (China clay), very dry and reduced to a fine powder. Before mixing with the kaolin, the paraffine must be heated to fusing point. Let the mixture cool, and it will form a homogeneous mass, which is to be reduced to powder, and worked into paste in a paint-mill, with warm water. This is the enamel ready for application. It can be tinted according to fancy.

ELECTROTYPING HANDWRITING.

To produce electrotypes or stereotypes of letters, signatures, ordinary written matter, drawings or sketches, coat a smooth surface of glass or metal with a smooth, thin layer of gelatine, and let it dry. Then write or draw upon it with an ink containing chrome alum, allow it to dry exposed to light, and immerse the plate in water. Those parts of the surface which have not been written upon will swell up and form a relief plate, while those parts which have been written upon with the chrome ink have become insoluble in water, after exposure to light. The relief may be transferred to plaster of Paris, and from this may be made a plate in type metal.

BLACK PAINT FOR BLACKBOARDS.

Take shellac varnish, one-half gallon; lampblack, five ounces; powdered iron ore or emery in fine powder, three ounces. If too thick, thin down with alcohol. Give the wood three coats of the composition, allowing each to dry before putting on the next. The first coat may be of shellac and lampblack alone.

TO CLEAN STEEL PENS.

Potato is used to clean steel pens, and generally act as a pen-wiper. It removes all ink crust, and gives a peculiarly smooth flow to the ink. Pass new pens two or three times through a gas flame, and then the ink will flow freely.

STATIONERS' WINDOWS.

It is important that strangers should get a good impression with a tasty window, or a polite reception when entering the store. Remember that first impressions go a great way, and when once formed, good or bad, are very hard to get rid of. Make it a special point to clean the window once a week, put in different stock every time, and do not be afraid to display goods because the dust will spoil them. If the article in question is delicate and easily ruined, leave it in the window only a few days; display samples of the latest goods, and, if necessary, buy some article that is showy, and which you think will attract people, especially for the window, even though the amount expended is "sunk." It will certainly pay in the end. If your stock of a certain article or class of goods is large, devote the whole window to it for a week.

It is impossible to give rules for the arrangement, which, of course, depends on the goods to be shown and the taste of the person dressing the window. Stamped papers and visiting cards can be shown effectively in the following manner:--Have a number of wooden blocks made the size of a quarter of a ream of paper and a package of visiting cards; wrap these neatly with a sample sheet of paper or cards on the outside, tied with ribbon. Another way to show printed visiting cards is to make a small pyramid of them by taking three small square boxes of different sizes, which, when placed one on top of the other, will form a small pyramid. Cover these entirely with samples of visiting cards, and place in the center of the window.

PHOTO-LITHOGRAPHIC TRANSFER PAPER.

Photo-lithographic transfer paper and ink are prepared in the following manner:--The paper is treated with a solution of a hundred parts of gelatine and one part of chrome alum in 2,400 parts of water. After drying, it is treated with the white of egg. It is made sensitive with a bath consisting of one part of chrome alum, 14 parts of water and 4 parts of alcohol. The latter ingredient prevents the white of egg from dissolving. On the dark places the white of egg, together with the ink with which the exposed paper has been coated, separates in water. The transfer ink consists of 20 parts of printing ink, 50 parts of wax, 40 parts of tallow, 35 parts of colophony, 210 parts of oil of turpentine, 30 parts of Berlin blue. It is found that a varnish formed of Canadian balsam, dissolved in turpentine, supplies a most valuable means of making paper transparent. The mode by which this is most satisfactorily accomplished is by applying a thin coating of this varnish to the paper, so as to permeate it thoroughly, after which it is to be coated on both sides with a much thicker mixture. The paper is kept warm by performing the operation before a hot fire, and a third and even a fourth coating may be applied until the texture of the paper is seen to merge into homogeneous translucency. Paper prepared according to this process is said to come nearer than any other to the highest standard of perfection in transparent paper. Care must be used in making, as the materials are highly inflammable.

DIFFERENT KINDS OF ENGRAVING.

"Line" engraving is of the highest order. All engravings are done in "line"--simply straight lines. Next comes "line" and "stiple." "Stiple" means dots--small dots like this:--....--.... These small dots are used to lighten up the high parts of the face or drapery. It is very hard to engrave a face in lines, simply, and only master engravers have ever undertaken it. The masters understand and practice both in "line" and "stiple." Claude Mellan engraved, in 1700, a full head of Christ, with one unbroken line. This line commenced at the apex of the nose, and wound out and out like a watch spring. Mezzotint engravings are produced thus:--The steel or copper is made rough like fine sand paper. To produce soft effects, this rough surface is scraped off. If you want a high place or "high light" in your engraving, scrape the surface smooth, then the ink will not touch it. If you want faint color, scrape off a little. Such engravings look like lithographs. Etching is adapted to homely and familiar-sketches. Etching is done thus:--The copper or steel plate is heated and covered with black varnish. The engraver scratches off this varnish with sharp needles, working on the surface as he would on paper with a pencil. Nitric acid is then passed over the plate, and it eats away at the steel and copper wherever the needle has scraped off the varnish. When the varnish is removed with spirits of turpentine, the engraving is seen in sunken lines on the plate.

HOW TO PRESERVE PENCIL SKETCHES.

The pencil drawings of mechanical draughtsmen and engineers may be rendered ineffaceable by the following process:--Slightly warm a sheet of ordinary drawing paper, then place it carefully on the surface of a solution of white resin in alcohol, leaving it there long enough to become thoroughly moistened. Afterward dry it in a current of warm air. Paper prepared in this way has a very smooth surface. In order to fix the drawing, the paper is to be warmed for a few moments. This process may prove useful for the preservation of plans or designs when the want of time or any other cause will not allow the draughtsman reproducing them in ink. A simpler method than the above, however, is to brush over the back of the paper containing the charcoal or pencil sketch with a weak solution of white shellac in alcohol.

CARE OF WOOD TYPE.

Wood type should always be kept in a cool and dry place--not, as is often the case, a few feet from a large stove, or directly over the lye and wash tub. The drawer or shelves--drawers or cases are preferable to shelves--where they are kept, should not, as very often happens, be made of unseasoned wood, for this reason: type wood is usually perfectly seasoned, and when allowed to remain for any length of time on a damp surface, the moisture is absorbed, the bottom expands, and a warped type, ready to be broken at the first impression, is the result.

Wood type should only be washed with oil. A moistened cloth is sufficient, is more economical, and is certainly much cleaner than using their weight in oil. All wood type have a smooth and polished face, and if properly cleaned when put away will last for years. In fact, proper use only improves the working qualities. Wood type forms should not be left standing near hot stoves, or left locked up over night on a damp press or stone to warp, swell, and perhaps ruin a costly chase.

COPPER-PLATING ON ZINC.

Take an organic salt of copper--for instance, a tartrate. Dissolve 126 grammes sulphate of copper (blue vitriol) in two litres of water; also 227 grammes tartrate of potash and 286 grammes crystallized carbonate of soda in 2 litres of water. On mixing the two solutions, a light bluish-green precipitate of tartrate of copper is formed. It is thrown on a linen filter and afterwards dissolved in half a litre of caustic soda solution of 16° B. when it is ready for use.

The coating obtained from this solution is very pliable, smooth and coherent, with a fine surface; acquires any desired thickness if left long enough in the bath.

Other metals can also be employed for plating, in the form of tartrates. Instead of tartrates, phosphates, oxalates, citrates, acetates and borates of metals can be used; so that it seems possible to entirely dispense with the use of cyanide baths.

TO TRANSFER ENGRAVINGS TO MOTHER-OF-PEARL.

To transfer engravings to mother-of-pearl, coat the shell with thin white copal varnish. As soon as the varnish becomes sticky, place the engraving face down on it, and press it well into the varnish. After the varnish becomes thoroughly dry, moisten the back of the engraving and remove the paper very carefully by rubbing. When the paper is all removed and the surface becomes dry, varnish lightly with copal.

METAL FOR STEREOTYPING.

For every six pounds of lead add one pound of antimony. The antimony should be broken into very small pieces, and thrown on the top of the lead when it is at red heat. It is a white metal, and so brittle that it may be reduced to powder; it melts when heated to redness; at a higher heat it evaporates.

The cheapest and most simple mode of making a stereotype metal is to melt old type, and to every fourteen pounds add about six pounds of grocer's tea-chest lead. To prevent any smoke arising from the melting of tea-chest lead it is necessary to melt it over an ordinary fire-place, for the purpose of cleansing it, which can be done by throwing in a small piece of tallow about the size of a nut, and stir it briskly with the ladle, when the impurities will rise to the surface, and can be skimmed off.

In the mixing of lead and type-metal see that there are no pieces of zinc among it, the least portion of which will spoil the whole of the other metal that is mixed with it. Zinc is of a bluish white color; its hue is intermediate between that of lead and tin. It takes about eighty degrees more heat than lead to bring it into fusion; therefore, should any metal float on the top of the lead, do not try to mix it, but immediately take it off with the ladle.

HOW TO FIX PENCIL MARKS SO THEY WILL NOT RUB.

To fix pencil marks so they will not rub, take well skimmed milk and dilute with an equal bulk of water. Wash the pencil marks (whether writing or drawing) with this liquid, using a soft camel-hair brush, and avoid all rubbing. Place upon a flat board to dry.

HOW TO OBTAIN A BRIGHT AND LASTING RED EDGE.

A bright and lasting red edge may be obtained by the following process:--Take the best vermillion and add a pinch of carmine; mix this with glaire, slightly diluted. Take the book and bend over the edge so as to allow the color to slightly permeate it; then apply the color with a bit of fine Turkey sponge, bend over the edge in the opposite direction, and color again. When the three edges have been done in this manner, allow them to dry. Next screw the book tightly up in the cutting press, and after wiping the edge with a waxed rag, burnish well with a flat agate burnisher.

TO RESTORE THE LUSTRE OF MOROCCO LEATHER.

The lustre of morocco leather is restored by varnishing with white of egg.

TO RESTORE THE ORIGINAL WHITENESS OF COPPER-PLATE, WOOD ENGRAVING, ETC.

The following process will restore the original whiteness of copper-plate, wood-engraving or printed matter:--Place a piece of phosphorus in a large glass vessel; pour in water of 30° centigrade (that is 86° Fahrenheit) temperature until the phosphorus is half covered. Cork up, but not tightly, the glass vessel, and lay it in a moderately warm place for fourteen hours. Damp the paper that is to be bleached, with distilled water; fasten it to a piece of platinum wire and hang it up inside the glass vessel. The faded paper after a short time will regain its original white color. It should then be taken out and washed in water; next drawn through a weak solution of soda, and finally dipped in pure water and laid on a glass table, and thus made dry and smooth.

FOR ELECTROTYPING ON CHINA.

For electrotyping on China and similar non-conducting materials:--Sulphur is dissolved in oil of spike lavender to a syrupy consistence; then chloride of gold or chloride of platinum is dissolved in ether, and the two solutions mixed under a gentle heat. The compound is next evaporated until the thickness of ordinary paint, in which condition it is applied with a brush to such portions of the china, glass or other fabric as it is desired to cover, according to the design or pattern, with the electrometallic deposit. The objects are baked in the usual way before they are immersed in the bath.

PAINTING ON EBONIZED WOOD.

The great difficulty to be overcome in painting on ebonized wood, is the non-absorbent character of the surface, which will not allow the paint to sink in. Washing the panel over with onion juice enables the paint to adhere more easily. The paint, whether oil or water color, must be laid on thickly. In order that the painting, whether of flowers or figures, shall prove a decoration, the black space between the painted figures must be graceful in shape. Water color paintings on such panels require to be varnished. Oil color does not need the varnish.

HOW GILDING IS DONE.

Letters written on vellum or paper are gilded in three ways. In the first a little size is mixed with the ink, and the letters are written as usual; when they are dry a slight degree of stickiness is produced by breathing on them, upon which the gold leaf is immediately applied, and by a little pressure may be made to adhere with sufficient firmness. In the second method some white lead or chalk is ground up with strong size, and the letters are made with this by means of a brush; when the mixture is almost dry, the gold leaf may be laid on and afterward burnished. The best method is to mix up some gold powder with size, and make the letters of this by means of a brush.

The edges of the leaves of books are gilded while in the binders' press, by first applying a composition formed of four parts of Armenian bole and one of sugar candy, ground together to a proper consistence; it is laid on by a brush with white of egg; this coating, when nearly dry, is smoothed by the burnisher; it is then slightly moistened with clear water, the gold leaf applied, and afterwards burnished.

In order to impress the gilt figures on the leather covers of books, the leather is first dusted over with very fine powdered resin or mastic; then the iron tool by which the figure is made is moderately heated and pressed down upon a piece of leaf gold which slightly adheres to it, being then immediately applied to the surface of the leather with a certain force; the tool at the same time makes an impression, and melts the mastic which lies between the heated iron and the leather; in consequence of this, the gold with which the face of the tool is covered is made to adhere to the leather, so that on removing the tool a gilded impression of it remains behind.

PRINCIPAL COLORS OF GOLD FOR GRINDING.

The principal colors of gold for grinding are red, green, yellow. These should be kept in different amalgams. The part which is to remain of the first color is to be stopped off with a composition of chalk and glue; the variety required is produced by gilding the unstopped parts with the proper amalgam, according to the usual mode of gilding. Sometimes the amalgam is applied to the surface to be gilt, without any quicking, by spreading it with aquafortis; but this depends on the same principle as a previous quicking.

WRITING ON METALS.

To write on metals, take half a pound of nitric acid and one ounce muriatic acid. Mix and shake well together, and then it is ready for use. Cover the plate you wish to mark with melted beeswax; when cold, write your inscription plainly in the wax clear to the metal with a sharp instrument. Then apply the mixed acids with a feather, carefully filling each letter. Let it remain from one to ten hours, according to the appearance desired, throw on water, which stops the process, and remove the wax.

HOW TO TRANSFER A PHOTOGRAPHIC PRINT TO GLASS.

To transfer a photographic print to glass for painting or for other purposes, separate the paper print from the background by steaming it; dry thoroughly, and having given the warmed glass an even coating of clean balsam or negative varnish, place the face of the print on the surface thus prepared, smooth it out and let it stand in a cool place until the varnish has hardened. Then apply water, and with a soft piece of gum-rubber rub off the paper so as to leave the photographic image on the varnished glass.

STEREOTYPING WOODCUTS.

In stereotyping woodcuts, care should be taken that they are thoroughly dry before being sent to the foundry, as the intense heat to which they are subjected frequently causes them to warp and split, especially if pierced.

TO GILD WITH GOLD LEAF.

Bookbinders use gold leaf in two ways--to gild on the edge, and to place gold letters on the binding. To gild on the edge, the edge is smoothly cut, put in a strong press, scraped so as to make it solid, and the well-beaten white of an egg, or albumen, put on thinly; the gold leaf is then put on before the albumen is dry; it is pressed down with cotton, and when dry polished with an agate polisher. To put on the lettering, the place where the letters are to appear is coated with albumen, and after it is dry, the type to be used is heated to about the boiling point of water, the gold leaf is put on, either on the book or on the type, and then placed on the spot where the lettering is desired, when the gold leaf will adhere by the heat of the type, while the excess of gold leaf loosely around is rubbed off with a tuft of cotton.

GILDING ON WOOD.

To gild in oil, the wood, after being properly smoothed, is covered with a coat of gold size, made of drying linseed oil mixed with yellow ochre. When this has become so dry as to adhere to the fingers without soiling them, the gold leaf is laid on with great care and dexterity, and pressed down with cotton wool. Places that have been missed are covered with small pieces of gold leaf, and when the whole is dry the ragged bits are rubbed off with cotton. This is by far the easiest mode of gilding. Any other metallic leaves may be applied in a similar manner. Pale leaf gold has a greenish-yellow color, and is an alloy of gold with silver. Dutch gold leaf is only copper colored with the fumes of zinc. Being much cheaper than gold leaf, it is very useful when large quantities of gilding are required in places where it can be defended from the weather, as it changes color if exposed to moisture; and it should be covered with varnish. Silver leaf is prepared like gold leaf, but when applied should be kept well covered with varnish, as otherwise it will tarnish. A transparent yellow varnish will give it the appearance of gold.

GILDING IN OIL.

In order to make good work in oil gilding there are several indispensable conditions which must be observed. First, a smooth ground. Second, gold size free from grit or skins. Third, in putting oil gold size on the work it must be dross black, ground in turpentine, and mixed with boiled linseed oil and a small piece of dryers; well sand-paper again, when this coat is dry. And now for the finishing coat of color, which should be flat, _i. e._, mixed with turpentine and a few drops of japanner's gold-size, but no oil. The dross black should be first ground in turpentine and the gold-size added after. When this has dried, varnish with hard drying oak varnish, leave for a day or two, and then rub down with pumice-stone powder, sifted through muslin; use a piece of cloth or felt wrapped on a small block of wood, and first wet the surface to be rubbed with water; dry with a wash-leather, and re-varnish. The ornaments are usually done with stencil patterns, and the lines are done with straight edges and lining fitches. Stencil patterns can be cut out of card paper. Before using, give a coat or two of patent knotting. For gilding panels, give a coat of buff first, then a coat of gold-size, in oil. When this has dried just sticky, press the gold leaf upon it with a ball of wadding, and leave for five or six hours, then rub over with a piece of soft wadding, and wash well with a sponge and cold water. The gold will not need any preparation before painting on, but if varnished afterward use pale varnish. Screens should be painted in colors to match the rooms they are intended to be used in. Birds, flowers and animals are the subjects generally introduced for this purpose. Birds should be painted toward the top of the screen, animals, flowers, etc., in the centre or at the bottom.

GLOSS PRINTING.