The fat of the chemical ink penetrates the stone in dry form as well as in fluid form, and makes the plate receptive to printing-color. If the dry ink is cut into long pieces and sharpened, it can be used much like lead or black crayon. If the stone is ground very smooth, the work can be made quite fine and resembles that done with fluid ink. The crayon, however, wears away too quickly. If the stone is ground rough, so that instead of a polished surface it has one resembling rough paper, the crayon work appears as a mass of dots that are coarser or finer according to pressure with the crayon, and produce an effect similar to crayon designs on paper. As almost every artist and painter knows how to use crayon, no particular practice is required for working on stone, and there are no obstacles such as the difficulty of using the steel pen.
That crayon work on stone is capable of high perfection, and that it can represent the essentials of a painting in a manner scarcely to be excelled by the best copper-plate engraver, has been demonstrated by many successful productions. Add to this that in no other style can one work equally fast, either on copper or stone, and we see that the crayon method is a genuine advantage for the art.
For crayon work the stones must be uniform and hard. They must either be new, or, if they have been used, they must be ground so thoroughly that all traces of fat are destroyed and removed absolutely to a degree where it is certain that they will not appear again and take color, even if the stone is etched only lightly. As soon as the plates have been ground true, they must be grained by strewing some fine sand or powdered sandstone on them and rubbing in all directions with a small piece of limestone. The work can be done dry or wet. Soap-water is best. It gives the stone a handsome grain. Practice is demanded to get goodresults without scratching the stone. The artist must decide for himself what grain he needs. I think that it would be good if the artist himself were to grain the stone in varying degrees according to the need of his design. For instance, a coarser grain might be good for foregrounds.
As soon as the stone has been grained, it must be cleansed perfectly from dust and dirt. It is best to pour clean water over it and wash it with a clean rag. The dust and sand must all be removed, otherwise they will not let the crayon reach the stone where it is used delicately.
When the design is finished, it should be set aside for a day, that it may take good hold of the stone. It does no harm to let plates rest for years before etching. Etching must be done by pouring. Painting the etching fluid on is dangerous because of the danger of taking away fine spots. About one hundred parts of water are used to one part of aquafortis. Everything depends on not etching a bit more than necessary. It is best to etch the coarser parts specially with a small brush and stronger etching solution, and it is very good to wash the stone with clean water after etching and let it dry completely before coating with gum.
When the stone has been prepared, it should not be cleansed at once with oil of turpentine, but should be inked-in first with a light printing-color. Only after it has taken this well should it be cleansed of the crayon and treated to a firmer color. In the first inking-in there should be very little pressure with the sponge or wet cloth when dampening it, as the lightest parts of the design are easily rubbed away before they have taken color. If such parts should vanish, the easiest way to restore them is as follows:—
Coat the plate with gum solution and wipe with a clean dry cloth till it is perfectly dry. Then take a flat, knife-like instrument of steel, which is cleanly ground so that it has no nicks or other defects that might injure the stone. Scrape with moderate pressure to and fro over the defective places, but only so that it touches the elevated points and not the surface of the stone itself. Smear a little fat, such as linseed oil varnish, over it and wash this away again instantly with gum solution. Generally the parts all reappear very nicely when the stone is inked-in again.
A second kind of correction is as follows: Ink the stone with firm color, wash it well with plenty of pure water and let it dry. Now redraw the lost places with crayon.
Printing crayon work is the most difficult of all lithography, but can be done perfectly if all necessary precautions are taken. These are mainly: (a) proper dampening of the paper; (b) perfect dampening of the stone;—too much meaning that the fine points will not take color well, too little making the stone smut easily; (c) good stretching of the leather, industrious lubrication, and an underlay of taffeta; (d) a good, finely mixed inking-color that will not shade off in printing and yet does not contain too much lampblack; (e) soft and well-dried ink-rollers; (f) proper tension of the press; (g) utmost possible speed in printing. The latter aids enormously, because the stone does not get so much time to dry out.
Aside from the spreading and running-together of the darker parts, one of the commonest faults of crayon work is that it is very liable to get a tone, which spreads over the whole design like a veil; or that the designs lose their firmness and appear "monotonic" because the shadings spread and thicken. The first fault comes from weak etching or from oil that was rancid when it was used to prepare the varnish. The latter fault makes the color adhere and smut the stone. The same fault is developed if the printing-color contains soap, which some printers mix into it for better adherence. It can occur also if the stone has lost its preparation owing to frequent cleansing and strong rubbing with a dry rag that is inky. Even strong rubbing with clean water can cause it if the rag contains fats.
As to the "monotonic" effect, it is frequent, and I have learned that it can be caused in two ways, namely, if the color is squashed continually during the print, which makes the stone sooty; or if the color spreads, as, for instance, during the night or during the noonday rest. The stone is prepared only on the surface. In the pen style, all lines are prepared on the sides also, so that they cannot spread because they are considerably more elevated than the crayon designs.
If a crayon design dries after printing and is not coated properly with gum, the color is liable to spread away from the design and give the platethe before-mentioned tone. Even if it is coated with gum, the color will spread, at least in the inner parts of the stone; and as soon as the very thin surface has been at all wiped away by rough usage, the underlying fattiness will appear gradually, and begin to take color.
Both faults of crayon work, namely, the taking of tone and the development of a "monotonic" condition, can be remedied by inking the plate for a while with a firmer color. If this does not help, the following must be resorted to: Ink-in the plate as well as possible, lay it in the etching-trough and pour over it very weak aquafortis once or twice. Then wash it with pure water and paint the gum solution over it. The etching must be done with great caution, with a solution so weak that the acid is scarcely perceptible. If the plate is to be saved at all without extensive corrections and re-drawing, this is the best way. If it is done correctly, it harms the design so little that I advise it even when the plate looks quite well, but has been standing very long after the first printing.
I have etched several crayon designs over again, and rather extensively, to make them more durable and facilitate printing, and with good success. This gives the further advantage that corrections can be made at the same time.
The correction of crayon designs, that have been etched already and used for printing, always has been so difficult a task that few have succeeded. This has led me to give the matter my best attention; and I hope that the following rules, based on many experiments, will show the way, at least, even if they do not produce absolute results.
When a copper-plate engraver has partially finished his plate, he can have a proof pulled to enable him to study his work. Then he can make corrections as he pleases,—an advantage that the stone worker has lacked hitherto.
To produce an impression that shall be faithful to all the beauties of a crayon design is a matter dependent on so many trivial details that of the many hundred crayon designs that have been produced by lithographers since the origin of the art, hardly one has realized the designer's hopes and ambitions. The commonest fault is that the more delicate parts ofthe design print too light and the heavier ones too dark, thus destroying the balance of tones. The lightening occurs because the finest parts of the design have lost their power of taking printing-color. The darkening occurs because the closely shaded parts flow together, either because the etching has not made enough white space between the points and lines or because they are squashed in the pressure of printing.
From this, two other faults may arise, that become visible after inking-in the plate: The first is the appearance of white dots, sometimes pretty large. The second is that black dots and smut-marks appear.
The white dots are caused by speaking during the work, and thus dropping spittle on the plate. If the spittle is mucous, the plate covers itself there with a fine crust that resists the chemical crayon so that it does not soak into the stone and is wiped away by the inking-in. If the spittle is fatty,—for instance, if one has eaten anything greasy,—the dots that appear will be black. The same results from touching the plate with fatty hands. Sometimes a whole picture of the fingers and skin will appear on the impression.
Let us suppose that after inking-in, a plate shows all these faults: the finest shadings vanished entirely, the darker places run together, white and black dots and smut-marks so that the plate has become useless in every respect. Can this be remedied? If so, how?
I answer that it can be remedied in every point; but that the artist himself must decide if it will not pay better to do the whole design anew.
The second question I answer as follows:—
Before everything else, it is necessary to remove all that should not be on the stone, all smut-marks and black dots; and where the design has darkened, white points or lights must be graved-in. To accomplish this, the stone is inked-in first with a firm acid-proof color, and over this with a lighter one. Then erase or grind away the dirt that is outside of the design and that would dirty the margin of the printing-paper. No erasing or grinding must be done within the design itself because then the grain would be destroyed and the necessary drawing could not be done as it should be. Therefore the faulty parts must be removed by engraving,with a more or less sharp needle of good steel, so that what remains looks quite like a good grain. A little practice will show that this work is not at all difficult and can be done quickly. Places that have run together can be cleared and made transparent and clean in a few minutes. If certain points have become too large, they can be corrected by engraving a white point in their centre or by engraving a line through them.
Here I must note that parts of crayon designs thicken sometimes because the crayon has slipped in drawing, without leaving traces perceptible at the time. If the etching is weak, it may happen easily that this place takes printing-color. Skillful engraving may not only correct the defect, but actually gives the design a beautiful tone and power such as cannot be easily produced by the crayon itself.
When the plate has been cleansed thus of all surplus and blemishes, weak aquafortis is poured over it several times and then it is coated with gum. After a few minutes it is inked-in with fairly firm color. Then it will be seen that the design is clean, but that all the parts that were too light are not darker, but perhaps even lighter, having been affected by the etching. To remedy this, coat the stone with gum solution and then wipe it off with a dry clean rag so thoroughly that only a thin film of gum remains behind. To judge this better, it is well to mix a little red chalk with the gum. When the plate is wholly dry, take a knife-like tool of steel as described before, and scrape the defective parts under moderate pressure, without injuring the elevated points of the design. Great care must be taken during this process to let no moisture, not even the breath, touch the stone, because that would produce the very opposite of what is aimed at. When all faulty places have been treated, a little tallow or linseed oil is smeared over the plate and then washed away well but gently with thin gum and water. If this manipulation has been done accurately, the lost parts of the design will appear when the plate is inked with a somewhat softer color.
Those who fear that they do not possess the skill necessary for this rubbing-up of the defective parts may attain the object by re-drawing them. The stone must be washed off first with a great deal of verypure water and the crayon must contain much soap. This kind of correction must be finished as quickly as possible and the stone should not be set aside for any length of time without a gum coating. If the corrections are extensive, it is better first to ink the stone well with acid-proof color and then to wash it in pure water and let it dry. Then if it is inked-in after the design is finished, and if weak aquafortis is poured over it and it is prepared with gum, it will keep for several months.
Slight blemishes, white specks, etc., can best be corrected by gentle touching-up with crayon during the proof-printing on the wet plate. It is understood, of course, that one can also work with pen or brush in a crayon design that has been already etched. Parts that are too dark can be made lighter by passing over them a few times with a brush dipped in weak aquafortis and then re-coating with gum.
These are about the best ways for correcting a crayon design that proves after etching to be imperfect.
I close with the following:—
(1) The tanners of Munich manufacture an inking-ball, made especially for printing, of sheepskin, such as I could not obtain in other places, like London, Offenbach, and Vienna. It is not white like alum-dressed leather, but yellowish, and the oil has not been completely washed out. I have had dogskin and thin calfskin worked in the same way and have found them even better, because of their greater durability. If a roller is covered with this leather, so that the side that was hairy comes outermost (not innermost as many do), it develops a decided property of taking-on color, probably because of its smoothness and elasticity. This aids much in spreading the color uniformly over the stone. The property is increased if the roller is dampened slightly before being inked; but on the contrary, if the stone is kept too wet, the constant moisture will gradually prepare the roller, so to speak, and it will take less color and let it go quickly, thus inking the stone badly.
If a roller has been used a long time, it loses its elasticity and softness and becomes useless for fine work. Still worse is a roller that has hardened from the drying of the ink. It is surprising to see what a differenceit makes if one has worked for a time with a poor roller and then replaces it with a good one. It is almost impossible to believe that the new impressions come from the same stone. I am inclined, therefore, to believe that the quality of the ink-roller has more effect on good impressions of crayon and fine pen work than even the quality of the printing-color.
As stated, it is well to change rollers frequently, and it is wise to clean them with linseed oil or butter after use to keep them soft and tender. In working on crayon designs of superior value I advise the use of new rollers.
(2) It has been remarked before that the color of the stone often deceives the artist as to the values and proportions of his work and that the designs always look better on the soft-colored stone than they do on the glaring white paper. This observation led to printing on paper tinted like the stone, and the results fulfilled expectations. There were difficulties however. The very best quality of this paper is extremely dear, and other qualities had the property of dirtying the stone, on account of the coloring-matter used for tinting them. Therefore the attempt was made to print the design on white paper and to color it afterwards. Here, too, there arose many inconveniences, so that at last there came the thought of laying a yellow tint over the impression by means of a second printing. This method proved to be not only the most economical and quick, but it had the further advantage that the margins of the paper could be left white, thus enhancing the value of the design. Hardly had it been used with success a few times before Herr Piloty conceived the idea of printing the high lights into the design with white printing-color, so that the impressions would resemble actual drawings. My experiments toward that end did not result satisfactorily, because no white oil color will print well enough; and I proposed that the high lights be engraved into the tint plate and thus permit the original white of the paper to show. So there came that kind of crayon impression with one or more tint plates, which has become so popular that various art connoisseurs hold it to be the triumph of the lithographic art.
To make and print these tone plates, I have thought out many ways; but as I am sure that they will suggest themselves to those who have grasped my text-book, I will describe only the best of them all.
Take a stone of good average quality, the best not being essential, and grind it as for crayon work with a grain not too coarse. When it is clean and dry, cover it uniformly with the following chemical ink, which must be laid on so thickly that it surely will resist the aquafortis sufficiently, yet not so very thickly that it will hinder the drawing-in of the lights later on.
The chemical ink for use on the tone plates is made of four parts wax, one part soap, and two parts vermilion. The two first materials are melted in a clean vessel over a moderate fire and then the vermilion is stirred in.
A piece of ink as large as a hazel nut is rubbed down in a clean coffee cup and then dissolved in rain water till it is just fluid enough to lie evenly and nicely on the plate when applied with a soft brush.
When the stone thus has been painted red, it must be permitted to dry thoroughly. When it is dry, a strong impression of the design is made on sized but well-dampened paper with a printing-color rather soft than firm. Before the paper has a chance to dry and thus to shrink, the red stone is placed in the press and the impression is laid on it face down. Use moderate pressure. The drawing will transfer itself to the red surface, but the paper will stick. Wet it with weak aquafortis till it is completely softened and permits itself to be removed. Care must be taken not to spoil the drawing by violent wiping and rubbing.
This method is easier if a special transfer paper is used. Coat well-sized, very clean paper with a thin paste of starch such as laundresses use for stiffening linen. This paper must not be dampened very much, because then it will not take the impression well. It also is removed from the tone plate by washing with weak aquafortis and it yields very easily, because the paste lets go of the color readily.
When the design has been transferred to the tone plate, take good iron instruments and remove the wax surface wherever the high lights aredesired. As the stone is ground rough, the scraping will produce only small specks at first, because the instrument will touch only the relief points. The more the scraping proceeds, the deeper it will go, till at last one reaches the bottom of the coating and thus obtains a white light. Experts can so manipulate the tint plates that the lights will be graduated from the softest to the most glaring.
As soon as the lights are drawn in, the margins of the drawing are scraped the same way. Then the plate is treated to several washings of pretty strong aquafortis, about twenty parts of water to one part of aquafortis. After coating with gum, it is ready for printing.
The most important requisite for this printing is a good arrangement that will insure an exact register of the second impression with the first, that the lights may appear exactly where they belong.
To achieve this, the practice used to be to draw two register marks on the stone holding the original design, which were transferred to the tint plate with the rest of the design. When the first impression was made, the printed paper was cut away exactly at the marked points, and laid accurately, on the tone plate, being guided by the two marks there. This was effective, but it had the fault that the paper had to be trimmed off carefully for each impression and that the slightest inaccuracy spoiled the register. However, it is very useful for printing proofs.
It is far better to have a printing-frame that is so fixed that it will never shift its position in the slightest degree. To this is fastened a little movable frame that has two steel needles whose position is adjustable at will. Lubricate the leather inside with wax and lay a sheet of white paper on it. See that the tint plate is so fastened in the press that it cannot stir out of place. Make an impression and take care especially that the two register marks print off well. Now set the needles in the little frame so that they will be exactly over these two marks. If, then, an impression of the design is laid on so that the two guiding-marks on it come exactly under the two needles, it will, of course, register perfectly. Of course the little frame must be so adjusted that it can be folded back out of the way before each impression, and the printing-frame must hold the sheets of paper so that they cannot move.
To color the tint plate, use a firm varnish tinted with umber, or any other color that will give the desired effect. New rollers are best, insuring a fine, even, unspotted tone.
(3) In rough-grinding the stones, it is difficult to prevent scratches and furrows caused by the coarse sand. No design of value should be made on such a stone, but if one is used, the defects should be touched up with chemical ink and a fine brush, as crayon will hardly do it.
(4) As the delicate places in crayon work are not durable, etching having the property of reducing the light portions and darkening the darker ones, I tried the method of drawing the lighter portions on a separate stone in rather stronger manner and printing from it with paler ink. The success was so great that I hope in time to produce true masterpieces with the aid of skilled artists, and here call attention to it in advance.
(5) After learning how to make a second impression over a first one, it is not difficult to pass on to printing with several stones and from that going on to color-printing. In the early days of my invention I tried color-printing with a crayon plate and had the best success by using stencils such as are used by the painters of cards. On oiled stiff paper I made as many impressions of a design as there were to be colors. Then all that was to be red was cut out from one stencil, green from another, and so forth. Then the stone was wetted, the stencil laid on it and the uncovered parts of the stones inked-in with the right color. After all the colors had been applied, I made the impression, which generally looked neat enough, but still resembled a sketchy drawing rather than a painting, because no color except black, zinc red, and dark blue permitted itself to be printed strongly enough. But by using several stones, each of which can be designed and treated according to the necessities of color, impressions can be made that resemble the English colored copper prints very closely, especially if the crayon and pen or brush methods are united.
(6) A stone plate may be etched so that it will have the roughness needed for crayon work. Grind it as clean and smooth as possible with pumice, pour aquafortis over it and coat with gum. Wash it well in water and dry with a clean cloth. Coat it very thinly but uniformly with tallow intowhich is mixed a little lampblack, so that one can see if the coating is perfectly even. With a small ball or roller covered with fine cloth, roll or pat the stone till it has a very uniform tone. Now pour a little diluted aquafortis on one end as a test to see if it penetrates uniformly through the fatty coating. Practice is needed to hit just the right thickness that the tallow coating must be. It must be thin, and yet sufficiently thick to resist the aquafortis somewhat, so that it yields only at those places where the roughness of the cloth on the roller has removed it more or less.
If the test is satisfactory, make a raised border of wax around the stone and pour the aquafortis solution on it. A solution of forty parts of water to one part of aquafortis is better than a stronger one because the stones are more equally attacked. As soon as the resulting bubbles are as large as the head of a small pin, the etching fluid is poured away quickly and replaced with pure water to get rid of the bubbles. Pour away the water and apply etching fluid again. Repeat this four or five times, according to the grain desired, and in the end wash the stone well with oil of turpentine to remove all fattiness. Then it must be washed with weak but very pure aquafortis, followed by a great deal of very pure water. After cleaning and drying very carefully with a clean rag, it is ready for use; and if the work has been well done, a grain will have been produced that is prettier and much more even than can be produced by rubbing with sand.
(7) The instructions given here teach how to draw on a stone that has been prepared beforehand with aquafortis and gum. This is not in the least inimical to the durability of the design if only the union of the gum with the stone has been destroyed again by washing afterward with diluted but pure aquafortis and every trace of this acid again has been removed by copious washing with pure water. If there is a considerable amount of the soap in the crayon, the good result will be greater than with an entirely clean stone, because, since it has already been etched twice, the etching after the design may be very limited, so that it is not harmful to even the most delicate shadings in the design.
(8) Some attempts made by me to etch crayon designs more powerfully than usual proved that the more delicate places would suffer, but if Irubbed them up with a flat knife as described before, they appeared again and I had the advantage that the whole plate was much better prepared than it is with weak etching.
(9) If a crayon plate is spoiled in printing through carelessness or lack of skill, the rules for remedying the trouble are the same as those named for pen work, and the judgment of the worker must decide which method is the most applicable. In general, it may be assumed that the best remedy for blurred spots is to draw them over again with crayon; and for smutted parts the best is to apply firmer printing-color, or to cleanse with oil of turpentine and gum and afterward ink-in with acid-proof ink, and then use light etching with weak aquafortis followed always by coating with gum and water.
In the pen and crayon method all the lines that are to take printing-color are drawn directly on the stone with a fatty preparation. But lithography has a unique way of transferring to the stone a drawing or inscription that is first put on paper with the fatty substance. This is possible only for lithography, and I incline to the belief that it is the most important of all my inventions. It makes it unnecessary to learn reverse writing. Everybody who can write on paper with ordinary ink can do so with the chemical transfer ink, and this writing can then be transferred to the stone and manifolded indefinitely. In Munich and Petersburg this method has been introduced for government work. The measures adopted in council are written during the session by the secretary, with chemical ink on paper, and sent to the printery. Within an hour impressions are ready to distribute among the members. I am convinced that within ten years every European Government will have a lithographic establishment.
In war the method would have a great value. It would replace the field printery, and it permits greater speed and secrecy. The commander need merely write his orders himself and have them printed in his presence by a man who cannot read, to be sure that his plans will not be betrayed. Theengineer officers can draw plans and have them circulated among the officers who need them.
Authors and scientists will find the method to be the means of circulating their works in manuscript very cheaply.
Even artists will respect the method when its gradual perfection enables them to draw their pictures on paper with ink or crayon and reproduce them.
Not from boastfulness, but from conviction of the importance of the method, have I thus recounted its advantages. I could fill a whole book with detailed explanations. I wish to gain friends for the method, that it may be improved to its ultimate degree by skilled artists.
The chemical ink used for the paper may be soft or firm. The paper may be specially prepared or not. The stone may be warm or cold. The design leaves the paper entirely and clings to the stone, or does so only partly. To describe all this would take too much space. I will describe only the method that I consider best, namely, a method under which the work is done with a soft ink, and transferred to an unwarmed stone. This is the quickest and surest, and has the advantage of not spoiling the original.
In a clean coffee cup rub down a piece, as large as a hazel nut, of the chemical ink described under the heading "Transfer Ink" in an earlier part of this work. Dissolve with rain water or soft river water. The amount of water is determined according to the need for fine or coarse work. In the latter case, the ink should be thinner, that there may not be too much ink in the design after it dries.
While the writing or design is drying, select a stone that either has not been used before or at least has been thoroughly ground off, and grind it down once more with pure and dry pumice stone without water, until it is certain that all parts of the surface have been rubbed down so thoroughly that the stone may properly be considered a new one. Clean away the dust with clean paper, fasten the stone in the press, examine the scraper to make sure that it is even, adjust the press for the proper pressure; in a word, do all that is necessary for good impressions. From this time on thegreatest care must be taken not to touch the polished stone with as much as a finger, not to mention keeping grease and dirt away from it.
As soon as every point in the design on the paper is perfectly dry, wet it on the reverse side with a sponge dipped into weak but pure aquafortis until the paper is quite soft. Lay it between waste paper sheets for a time, to prevent it from pulling out of shape and to remove the excess moisture. It must be soft, but not wet, when the impression is made.
Lay the paper face down on the stone. On it lay two sheets of dry waste paper, then an equally large piece of taffeta, another sheet of waste paper and make the transfer print with a moderately swift motion of the press, which must have more tension than is used for ordinary impressions. The power of a lever press is insufficient for larger stones, and a cylinder press is required.
After a few minutes the stone is withdrawn from the press, the paper is lifted off and the stone permitted to dry for a minute. It is better if one can wait longer. Then put it into the etching-trough, and pour over it, quickly and only once, a clean but weak solution of one hundred parts of water to one part of aquafortis. It is necessary to be skillful enough to cover the whole surface with one application. Then the stone is washed by pouring pure water over it, and, if time permits, set aside to dry. If time is limited, the gum solution to prepare the stone can be put on at once. Now the transfer is on the stone, properly etched and prepared. To make clean impressions, however, the printing-color must first be rubbed on, then the stone must be inked-in with acid-proof color and after that undergo another etching, a trifle stronger.
To rub on the printing-color, rub a little acid-proof color into a piece of clean linen or cotton, so that it is well permeated but not thickly covered. Rub this rag gently to and fro over the transfer while the gum is still on it, till every part of the design is nicely inked. This rubbing-in of color is an important part of many of the processes that will be described later.
Now clean the stone well with water, ink-in with acid-proof ink, and etch it again as has been described several times. Then it is ready for printing. The last etching is not necessary if only a few impressions are desired.
Transfer is applicable not only for pen designs but also for crayon. The crayon used for the purpose should be softened a little with tallow, or, if the harder crayon is used, the stone should be warmed when making the transfer. But it must not be inked-in or have color rubbed on, until it is quite cold again. For crayon transfer the paper used generally is fine drawing-paper. It must be wetted with somewhat stronger aquafortis that it may release the crayon more readily. The rest of the process is the same.
Besides these two methods, the transfer process can be used for all products of the book-printer's art, type as well as wood-cut. A freshly printed sheet can be transferred directly to a stone, especially if the printer has used our before-mentioned acid-proof ink instead of his ordinary printer's ink. To get a perfectly clear transfer it is necessary merely to see that the printer does not use too much overlay, which would stamp the type too deeply into the paper; and that before trying to transfer the printed sheet to the stone it is subjected to gentle pressure in the press to free it from all inequalities. To do this without at the same time risking any loss of ink which might subsequently weaken the transfer, the sheet is well wetted, laid on a clean, wet stone that has been prepared so that it will not have any inclination to take color, and subjected to a very slight pressure, the press being used with almost no tension. This makes the printed sheet beautifully even. Then if it is transferred to a stone properly prepared as described before, the transfer will be perfect.
Even old book pages can be freshened up and transferred. I have spoken already of those that are on unsized paper. With prints on sized paper the method is as follows:—
Make a paint-like mixture of fine chalk and starch paste. Thin it down with water and paint the sheet. Dip a bit of linen rag into a thin color made of thin varnish and tallow tinted with vermilion. Touch-up the wet paper with the rag till every bit of type has taken red color. Pour clean water over it and touch-up the paper everywhere with a ball of fine cloth stuffed with horsehair. This will remove all surplus color. Continue this till the type matter is only faintly red. Then the paper must be washed very thoroughly with many pourings of water and laid between wastepaper sheets to remove all surplus moisture. The transfer and so on must be done then as in the other cases.
Good transfers can be made also from a copper-plate engraving if the copper-plate impression is made with our acid-proof ink. The ordinary copper-plate ink is not so good. It will be self-evident that designs on stone can be transferred and reproduced the same way.
The tracing process has the property in common with the transfer process that it transmits only a small amount of fattiness to the stone and requires subsequent rubbing-in of color to give it strength.
Coat a piece of thin and clean vellum paper with tallow and lampblack and wipe it off again as neatly as possible, so that there remains only a thin film, which will not smut the stone when laid face down, unless pressure is exerted. Now draw on this with a clean English lead pencil that contains no sand, or with a composition of lead, zinc, and bismuth, and the pressure will force the design on the stone and transfer its fat, which then penetrates the stone and will give impressions. In preparing a stone thus made, greater care in etching is necessary than even in the transfer process. Very weak aquafortis solution must be used.
The process is something between pen and crayon work. It is quite applicable for sketches and pictures that are to be illuminated.
For this purpose, the stone is coated completely with chemical ink on the places where this style is to be used. As soon as it is dry, the lights are drawn into it with a steel engraving-needle that is ground to a sharp or broad point according to requirement. Those parts that are to be very white, with fine lines and specks, are best drawn in with the pen. Thus the wood-cut style differs from the ordinary pen design chiefly in character and in the treatment of the darker parts. Its practice is much easier on the stone than on wood, and it can be combined with crayon work. Etching, preparation, and printing are the same as with other styles.
One of these resembles the wood-cut style in method but in effect approaches copper-plate work. The stone is grained as for crayon, etched, prepared with gum, cleansed with water, coated well with soap-water, wiped, dried, and finally coated with a thin, colored covering of fat, by either coating with acid-proof ink or with hard chemical ink.
This first etching and preparation are required to prevent the fat to be applied afterward from penetrating too deeply into the stone, so that it may adhere only to the surface.
Now the design is made on it with a steel scraper. The manipulation is like that for making tint plates. It demands greater care, however, and better etching.
The completed design is etched (phosphoric acid being best) and coated with gum. A few drops of oil of turpentine are poured on and all the color is wiped away with a woolen rag, but without any rough rubbing. Then the plate can be inked-in with fairly firm acid-proof ink.
The second method would excel crayon work if it were perfected. I have advanced pretty far with it. It is an imitation of the ordinary wash drawing which is done with a brush and dissolved Chinese ink on paper.
The stone, which must be very clean and free from all fat, is grained, coated with soap-water, cleaned with oil of turpentine, and dried. Then a hard chemical ink, which may contain a little more soap than usual, or the ink described for brush work, is dissolved in pure rain water and used on the stone with a brush just as it would be used on paper.
When the design is finished and very well dried, the entire surface of the stone is rubbed gently with a fine cloth, in order to perforate the color with tiny holes everywhere. As it will perforate more readily in the parts where the ink has been laid on thinly, the succeeding aquafortis will eat through there more easily, and thus the etching will correspond nicely with the tones of the design. It is necessary, however, to know the strength of the acid and the resisting power of the ink very accurately. It is well toexperiment and write down the best proportions. In any case, the etching fluid must not be too strong and the etching must not be done by pouring or brushing, but in the copper etcher's manner, by framing the stone with wax so that the fluid will lie on the stone. As soon as the resulting bubbles reach the magnitude of a pin's head, the fluid is poured off instantly and then poured on again till the bubbles reappear. How long this must be continued depends on the strength of the ink.
It is understood, of course, that the etched stone must then be coated with gum.
This speedy and easily executed style surely will come into wide use soon. It is done as follows:—
The outlines of a design are laid on a stone prepared for pen work, by tracing. Then they are traced again, say four times, on sheets of paper. On each sheet everything that falls into the category of one of the four chief tones is cut out with a sharp penknife so that the four sheets are like the stencils of card painters. Now the chief lines of the design are made on the stone with chemical ink, using either brush or pen. Lay one of the stencils on it exactly, weight it that it may not move, and perform the operation of spattering.
This is done by dipping a small brush, such as a clean toothbrush, into chemical ink and scraping it with a knife so that the ink is spattered over the stone. Care must be exercised not to have too much ink in the brush, for fear of blots or over-large spattering. After practice it will be possible to produce such fine and uniform dots as cannot possibly be produced by the pen. After the desired grade of shading has been achieved, the stone is permitted to dry. Then the second stencil is laid on and the operation repeated till all have been used. If enough stencils are made, the whole design can be made by spattering. It is not necessary, however, to make many, as the design has to be finished up by hand afterward anyway.
This finishing-up is done first with the engraving-needle, which opensand decreases all dots that are too large, and then with the pen, which brings out the true proportions of the various tones.
This really is only a process of using many tint plates. It makes splendid effects possible, equal to any produced by an artist with Chinese ink, and deserves the attention of all artists, especially as it is the easiest and quickest of all methods, even though it is a little circumstantial in the printing.
Draw the outlines of a design on the stone in chemical ink with pen or brush, and then make four, five, or six transfers on stone plates prepared for pen work. Register marks must be on the design. Now draw-in the darkest parts on the first plate, the less dark ones on the second, the lighter ones on the third, and so on till the whole design is finished. The work is best done with a brush. One or more of the stones may be designed with crayon; but the number of stones designed with ink must be greater, in order to make the grain of the crayon designs unnoticeable.
The etching is done as in pen work. For each stone the printing-color is chosen according to the tone of its design. Of course particular accuracy is vital; but the artist should not permit the apparent difficulties to frighten him, as he will see very soon after trial that no other method produces such beautiful results.
This method, in which the various colors are drawn on several stones, either with pen or crayon, resembles the one just described.
According to treatment the impressions will resemble a painting, a copper-plate engraving in color, or an illuminated copper-plate engraving, if the color stones are used merely to lay colors over a design already printed in its entirety in black.
The whole process is so like the preceding one that I need merely recount the colors that I have found serviceable for the purpose.
Red.Vermilion, red lake of cochineal, fine madder lake, and finally carmine if it is mixed first with Venetian turpentine before being combined with varnish, as otherwise it inclines to separate from the varnish and unite with water, staining the whole printing-paper red.
Blue.Berlin blue and mineral blue. Use only a small amount, sufficient for a few hours. These colors dry quickly, and, besides, make the varnish too tough, so that they must be thinned down from time to time with a little linseed oil. Fine indigo is very good, also a blue lake that is made of logwood and verdigris. This latter is not durable in sunlight.
I have had no success as yet with green or yellow.
Verdigris is difficult to manipulate because it smuts the stone easily and does not tolerate many mixtures. Schweinfurther green, one of the new colors, is much better in all respects, but not dark enough. Mixtures of yellow lake with indigo or mineral blue are not very durable. Golden yellow ochre with mineral blue or indigo does not produce a pretty green, and King's yellow mixed with blue is handsome but not durable. Neapolitan yellow and the newer chrome yellow with blue produce a green that is not dark enough.
I have obtained the handsomest and darkest green by printing the design blue first and then printing over it a yellow plate, so that the yellow lay over the blue. By using Berlin blue and fine ochre a fairly handsome color is produced. On account of its loss of color in water, ochre cannot be used unless Venetian turpentine is first mixed with the varnish.
A handsome and at the same time dark yellow is equally hard to obtain. Till a good color is invented, we must content ourselves with ochre, Terra de Sienna, Neapolitan yellow, mineral yellow or chrome.
This printing with various colors is a process for which the stone is superior; and it is susceptible of such perfection that in future true paintings will be produced by its means. My experience convinces me of this.
This process is useful for decoration.
Those parts of the design that are to appear in gold or silver are drawn with chemical ink on a stone prepared for pen work. After the drawing is dry, it is etched and prepared in the usual way. The printing is done with a silver gray color of firm varnish, fine crayon and a very little lampblack. The paper must be entirely dry and very smooth. Soon after the impression has been made, the printed parts are covered with silver or gold leaf such as is used by gilders. It is pressed on slightly with cotton, that it may adhere, and then a sheet of paper is laid over it. Then the second impression is made, treated the same way, and so on.
No more impressions must be made than one can cover with silver or gold in two hours. If the ink is on the paper too long, it will draw in and not take the metal well. After gilding or silvering, the sheets must lie for some hours or till the next day, that the ink may take perfect hold of the paper, so that, in the succeeding pressing, it will not penetrate the metal and make it look sooty. The pressing is done by laying six or eight impressions on a clean stone under the press and passing them through as for printing, with the proper tension. This tension must be adjusted according to the firmness of the printing-color; therefore it is best to make test with one sheet. Then, if the metal does not adhere sufficiently, the pressure can be increased.
In the end all surplus gold or silver is removed by gentle wiping with clean cotton. This is easy, as it will have fastened itself only to the printed parts. If the impressions can be set aside for some days without being wiped, it is better, and there is not so much danger of injuring the brilliancy of the metal.
If gold and silver are to be printed on designs where there is other color also, or where there is black, the print on which the metal is to be applied must always be made first. Only when the sheets have been gilded or silvered, pressed, wiped, and cleaned, is the black design to be printed onfrom the next plate. That all this must be done with the register marks previously described is, of course, self-evident.
So I close my description of the Relief method; and I hope that I have made it all so clear that good results will come to all who follow my directions.
This differs from the other in that the fat, which is to attract the printing-color, is under the surface of the stone, the design having been either engraved-in or etched, and then filled with fat.
Like the preceding method, it has several branches. The best are these:—
This is one of the most useful branches of lithography, and if the artist has attained enough skill and the printer knows his trade, it approaches very near to the handsomest copper plates, and at the same time is about three times easier and quicker than work on copper. It is splendidly adapted for writings and charts.
Choose a hard, uniform stone of the best kind. Grind it as finely as possible. Etch with aquafortis and prepare with gum. This, at least, was my early method, and it has remained in use in all printeries. Later, however, I discovered that it is almost better to coat the stone with gum without previous etching, because it can be more easily worked then. Only in that case it must be perfectly clean and contain no concealed fattiness. Immediately after the stone has been coated with gum (not some hours later, as many do) the gum must be removed with water, that it may not penetrate too deeply and thus cause a condition which will prevent the finest lines from taking on color subsequently.
Then coat the plate with a tint made of gum solution and lampblack orred chalk. Use a soft brush to make the coating very thin and uniform. It has the double purpose, first, of giving the stone a color so that the engraver can see his work, and of covering the prepared surface of the stone with a protective coat that later will admit the fatty printing-color only where it has been pierced by the engraving-tool. It is evident that this latter property is increased according to the amount of gum in it, yet only little gum must be used in it, the permissible amount being only just enough to insure that the coating shall not be easily wiped away during the work of engraving.
The stone must be absolutely dry before any work is done on it. Then the design is traced on it, or drafted directly on it with lead. Transfer by printing from paper is not advisable, because the resulting fattiness of the design makes the graver slip.
For the actual work of engraving there is no counsel to be given except to choose good and sharp needles of the very best steel, hard enough to cut glass; and that all lines must be graved clean. There must be no excessive pressure, and in wide strokes there must be no excessive depths. In making very fine lines the stone should merely be touched by the tool. If they appear white, and a little fine dust is observed, one may be certain that they will appear properly in the printing. Broad lines often can be made with one stroke of a flat needle, but generally they are made by continued, gradual scraping. If the stone is to be only lightly wiped during printing, the broad lines must not be deeper than strictly necessary to make them clear, as otherwise they will squash. In true art works, however, which are to be printed with firm color and under more powerful rubbing and wiping, the depths of all lines must be considered carefully, as they will print darker or lighter according to depth.
Of all things the worker must take heed against touching the stone with dirty or greasy hands, for a plate thus blemished is not only difficult to engrave, but the grease finally may penetrate through the slightly gummed coating and enter the stone, making much consequent trouble when the printing begins.
It is more harmful still to wet the stone in any way, because then thecoating gum will dissolve, penetrate into the engraved lines and give them a preparation, so that they cannot take color afterward. Therefore, especially in winter, a very cold stone must be warmed before working on it with the design, as otherwise the moisture in the room will precipitate itself on the stone. Even the perspiration of the hands or the moisture of the breath may cause damage. Therefore a good but careful warming is very advisable.
If a plate has become moistened, as, for instance, from a breath, it must be permitted to dry before doing any further work on it, and especially it must not be wiped.
The dust resulting from the engraving is to be removed either with a soft brush or by blowing it away.
Faulty lines that are noticed during the engraving may be scraped flat very carefully so that no furrows are made, or they may be rubbed off with fine pumice, after which those places must be prepared again, and coated with gum applied with a small brush. Then the corrections can be made. If only tiny places are faulty, they need merely be coated with a mixture of weak phosphoric acid, gum, and lampblack or red chalk. This prepares them. Thus they will not take color during the print, and so are practically removed.
When the design is finished, the stone must be very dry that it may take color well. But it must not be warmed, as this would incline it to take smut. A color consisting of thin varnish, a little tallow, and lampblack is now rubbed swiftly into all the depressions, and immediately wiped away again with a woolen rag wetted with gum solution. This removes the original red or black coating also.
Thus the hitherto colored stone becomes perfectly white, while the engraved design, which has appeared white, is now black. The first impression that the eye will gain will be that now the design appears much finer than it did before. That is because every white line on a dark background looks wider than a black line of the same thickness on a white background. Therefore, while engraving, the artist should aim to make his lines a trifle bigger than his eye would suggest.
In printing the stone the usual precautions required in every form of lithographic printing must be observed. Beyond that, the matter of chief importance is the proper composition of the printing-color.
Stone plates made in this way can be inked-in (1) by rubbing-in the color and light wiping, and (2) by harder wiping, and (3) by the ink-roller.
For the first method, a color can be made of thin varnish and burned lampblack, the latter being present in fairly large quantity but very finely rubbed-down. Into this color is mixed a quantity, equivalent to one half the mass, of gum solution that is almost as thick as the color itself. Everything must be mixed perfectly. If the solution is too watery, it is not easy to mix it.
Three clean rags of cotton or linen are needed for inking. The first is used to wet the stone and to clean it again in the end. The second is colored with a small quantity of printing-color and rubbed in by thorough wiping to and fro. The third rag is used to clean away any surplus that may adhere. Then the first clean rag is used to cleanse the stone thoroughly.
All three rags must be wetted with gum solution, and the first and third must be washed several times during the day.
The stone plate is harder to clean at first than after some fifty impressions have been made. Often there will remain little specks of color on the prepared places, which are easy enough to wipe away but are inclined to reappear. To remedy this it may be necessary to use more clean rags in the beginning or more gum solution. If the stone has been polished very well in grinding, this trouble will not be very noticeable if at all. Under any circumstances, it will disappear gradually during the printing, so that at last it will be possible to clean the surface with the very same rag that lays the color on and is permeated with ink.
In the second method, the wiping is harder in order to take more color away from the shallower lines, so that they will be pale compared with the deep ones which then will appear very black and strong.
If the full beauty of a well-made copper plate is to be equaled, care must be taken, as said before, to achieve the proper depth of engraving,and the stone must be wiped harder. Otherwise the method is the same, except that beautiful, shining impressions often can be made by using a firm color, if the stone can bear the necessary tension.
The inking-in with the ink-roller is like the same process in other methods, except that the color must be softer and the roller well filled with it. It is necessary, also, to learn by practice how to work the color into all the deep lines.
The impression must be made immediately after inking, as otherwise the color will sink too deeply into the stone and not give a strong impression without renewed inking.
The paper must be wetted a little more than in the other method.
The tension of the press is according to the size of the plates, but on the whole must be two or three times greater than for the other methods. More pressure still may be needed for very fine work, as the finer lines often are harder to print than the coarse ones.
As soon as the first clean proof is pulled, it must be examined for errors or faults in the design. If there are any, the stone is removed from the press after being delicately coated with gum, and the correction is made as follows: Before anything else, all such faults as are to be removed entirely are either scraped away with a very sharp knife or rubbed away with a very fine stone. The manipulation must be very delicate to avoid grooves and furrows or sharp edges that afterward will hold dirt. Then the parts thus corrected are coated with a mixture of about six parts water, two parts gum, and one part aquafortis to prepare them anew.
If anything new is to be added to the design or drawn in place of an error, the stone is washed with water throughout, or, if the correction is to be made only in a very small part, washed at the desired place. Then it is coated with the red chalk as described in the beginning, but so thinly that the design can be seen plainly through the red coat. Now all that is desired can be engraved, filled again with the rubbing-in color, and turned over to the printer, who cleanses it with gum water and proceeds to print.
Only a few more useful suggestions:—
(1) It happens often that after the first rubbing-in of fat color and thesucceeding cleansing with water, the stone gets a "tone" over its whole surface; that is, it takes color at least partly, and thus seems to have lost its original preparation. This may be due to the fact that not enough gum has been used in the original coating, or that the rubbing-in was rough enough to injure the protective coating, or that the rubbing-in-color was left on too long before being washed away with gum solution.
A similar fault may develop with the second rubbing-in, after corrections, and from the following causes: Poor color containing sand; too much pressure with the greasy rags; the use of rags not sufficiently cleansed of any soap used in washing them; rubbing-in of color with too dry a color rag; in brief, from anything that may destroy the stone's preparation wholly or in part.
Sometimes this defect may be remedied by mixing more gum into the printing-color and into the water with which the cleaning-rags are wetted. A firmer color may aid, if it is rubbed away by fairly strong pressure of the rag as soon as it has adhered. This operates as a remedy because the firm color takes hold of the dirt that has set itself into the pores of the stones, and when it is removed, takes the dirt with it. If none of these have results, there is nothing left except to grind off the plate very slightly and carefully with an exceedingly fine stone and gum solution. In the case of very delicate designs, this is not applicable, because the finest lines have practically no depth. Therefore they must be washed instead, a rag being dipped into weak aquafortis or very much diluted phosphoric acid, and passed carefully over the stone till the dirt disappears. It is well to mix in a little gum, and also to rub acid-proof ink into the stone first, that the etching fluid may not attack the design too much.
After this cleansing the tone will disappear, but another fault often appears in place of it. The color, after rubbing-in, will not permit itself to be wiped away readily, because the etching has caused some roughnesses to which the color adheres in the form of little specks. A number of clean rags with gum solution must then be used, or the stone should be lightly rolled a few times with the ink-roller after being rubbed-in. The roller will take the specks. Indeed, the fault hardly ever appears if the inking-inis done with the roller, as suggested in the remarks about the third form of inking-in.
As soon as some few impressions have been made, the roughness of the plate disappears gradually and it can be wiped off without leaving specks behind. Gentle rubbing with pumice finely powdered and mixed with gum solution will remove the defect in the very beginning, but care is needed lest the design be injured.
(2) A line that has so little depth that it is almost level with the surface of the stone can be made as black as a deeply engraved one by continued rubbing with the color rag. In using a firmer color the lines, especially the wider ones, can be so overloaded after a while that the ink will squash under the press. This surplus can be removed again by the use of the ink-roller, but it is merely adding unnecessary work, as proper practice in inking-in and the use of exactly the right consistency of color will prevent the trouble.
(3) The best way to ink-in an intaglio design is to rub it in at first with a somewhat firm color that however, contains enough gum, then to wipe it a bit, and after that to rub gently to and fro over the stone under gentle pressure, with a rag containing a less heavy color. A firmer color does not adhere well to the more delicate lines, or, at least, is hard to print; but by applying it first, the printing of the wider and deeper lines is facilitated, while the succeeding rubbing with softer color brings out the perfection of the finer lines.
The second rag with the lighter color must not be filled with it in mass, but should merely be made sooty with it, so to speak. Otherwise the lighter color would penetrate the deeper lines also and mix there with the heavier color.
In the end the stone must be wiped again with an entirely clean rag, as will be understood, of course, and thoroughly cleansed of all the color.
In this the design is not engraved into the stone by pressure of the hand, but with aquafortis or other acid, and only so much pressure is exerted in making the design as is required to cut through the thin coating of varnish with which the stone is covered. Therefore this method permits great freedom of action and is applicable especially for landscape work and for drawings in Rembrandt's style. In treatment as in effect it resembles copper plate, and has its own advantage in that the lines may be strengthened gradually by stronger pressure on the engraving-needle. They may even be engraved a little into the stone so that afterward the lines will become stronger under etching. This cannot be done with copper at all or only with great difficulty.
These considerations and the quicker printing permitted by it recommend the method to artists. In other respects it is not different from working on copper. But it is necessary that a good lithographer should be a master of this form of stone work, as it may be used for excellent work, not only by itself but in combination with the other methods.
The stone must be ground as smoothly as possible, then treated with aquafortis and coated with gum, so that its surface thus is completely prepared. The aquafortis may be as strong as that used for etching pen work. It suffices, also, to wipe the plate merely with a sponge dipped in stronger aquafortis, the chief point being that no roughnesses shall be caused by uneven etching.
A few minutes after this first operation is finished, the stone is rinsed with water, dried and coated with etching-ground. This can be best done as follows:—
(1) Warm the stone till an ordinary copper etcher's etching-ground will become so fluid on it that it can be worked with a leather ball like a varnish, and can be spread very thin and very evenly. Great care must be exercised lest uneven warming crack the stone. If one can put it into a nearbybaker's oven, it will obviate the necessity for an especial apparatus, which otherwise is demanded.
After coating the stone with the etching-ground, it is reversed while still warm, and blackened by applying the flame of a tallow or wax candle, as the copper-plate etchers do with their plates. Then the stone is set aside to cool, with great precautions against dust. After it is cool, dust will not harm it, and it can be kept indefinitely before use, so long as the coating is protected against injury.
(2) The method given is the best; but if the warming of the stone is difficult, there is a method applicable to cold stones. The etching-ground is dissolved in oil of turpentine and laid on the stone with a clean ball. A stone so treated must be put away for at least a day in a place safe from dust that the oil of turpentine may evaporate.
To tint this etching-ground, it may be blackened by smoking with a candle, as in the first case; or color, such as lampblack or vermilion, may be mixed-in before it is applied. If one wishes to be very certain that the stone will bear the etching well, it may be coated, very thinly indeed, with a solution of very firm chemical ink after applying the etching-ground.
The design is traced through this coating to the stone. It may be transferred, also, but in that case, as soon as the transfer is on the stone, it must be coated thinly once more with a solution of chemical ink that does not, however, contain any lampblack or other coloring-matter, but is transparent. This is necessary to fill out any little holes and other injuries that may have been caused by the pressure during transfer or by the inequalities in the transfer paper.
The designing with the needle is done as in the engraved manner, except that the design is merely cut into the coating.
When the design is complete, the stone is laid into the etching-trough and diluted aquafortis, muriatic acid, or strong wine vinegar is poured over it repeatedly, according to the depth that the lines are to have.
If it is desired to etch so as to produce various tones,—some strong and some delicate,—after the manner of the copper-plate etchers, the pouringof acid should cease as soon as the very finest lines of the design have been etched sufficiently. Wash away every bit of acid with clean water and let it dry. Then, with a small brush and chemical ink, coat all parts that are not to be etched further. It is well if the chemical ink used for this purpose contains a little more soap than usual, so that it can penetrate well into all the depressions and leave no little holes. The coating must be done very cautiously, and it is better to paint on too much ink rather than too little, as the design will appear very dirty if etching fluid should penetrate here or there through the coated portions.
When the ink is dry, etching is resumed till the second tones have been etched as far as desired. Then the procedure is repeated, these second tones being coated. Thus one continues till all gradations of shading have been reached.
When the stone is fully etched, clean water is poured over it, and then all the parts that have not been coated with chemical ink are treated to a covering. The object of the previous coatings was to prevent access of acid to the parts; but at the same time the ink prepared the parts. Therefore the remaining portions of the design also must be sated with ink before the stone is inked-in for printing.
Let the stone dry and then pour on it as much oil of turpentine as may be necessary to dissolve this whole ground coating, which then is wiped off with a woolen rag wet with gum solution. Then the stone maybe inked-in and printed.
If an error is observed before etching begins, the first question is if the defect is deeply engraved in the stone or if it has been drawn merely through the ground coating without affecting the stone itself materially. In the latter case it is necessary merely to cover the defective place with chemical ink and draw into it the correction. If the error has been graved deeply into the stone, it must be covered for the time being, but nothing new can be drawn there. To do this, one must wait till the plate has been etched and rubbed-in with color. Then the incorrect part is scraped or ground off as evenly as possible, the place prepared anew with aquafortis and gum, and the correction made with the steel needle.
An intaglio design often is greatly beautified by being printed with a tint plate like a crayon design. It can be done with a second stone, but it can be obtained also with the one plate that has the design on it. Wash the designed stone with clean water and then paint a thick coat of chemical ink containing more soap than usual over the whole stone or over only such parts as one desires to improve by adding a tone. If lights are to be worked into this tone, it can be done, after inking-in, with a small brush dipped into weak aquafortis.
In printing a stone thus toned, it must be rubbed-in thoroughly with the black color and then cleaned as well as possible. The tint that shows on the surface then is usually too dark, and the firmer the color the darker it is. Then a second rag must be used with a much softer color, which may even be thinned-down with plain oil or butter. It may also contain another coloring substance. Rub this rag very gently to and fro without much pressure till it is apparent that the dark tone has been replaced by a light one. Then the stone is ready for printing.