The Invention of Lithography Part 16

CONCERNING OTHER APPLIANCES

These are: a grinding-table, an etching-trough, some rulers, a writing-table, some music-writing pens and rastrums for those who wish to print music, small brush for spatter-work, a wiping-machine for the wiping method, several rollers and b.a.l.l.s for inking, and some presses for wetting and pressing the paper.

Any firm table may be used for grinding, but it is better to have one made heavy enough to resist the strain of the powerful friction, and so made that the stones can be fastened on it readily. If this work is done in a room, it must have a depression in the middle and a hole, that the water may run off into a receptacle. Along the sides should be a low rim, that the sand and dust may not drip all over the floor.

The etching-trough is a square, well-pitched box whose bottom is depressed toward the middle, that the etching fluid may gather there and run through a hole into a receptacle, so that it can be poured over the stone again. The trough must be large enough to accommodate the stones easily. These must not, however, touch the bottom, but must rest on little pieces of wood or cross-pieces.

Besides the ordinary rulers, a large, broad one is required, about three to four feet long, five inches wide, and so shaped that on one side it is one-half inch thick, on the other only two lines thick. On this latter side a strip of pear wood must be glued and very truly planed off. Thus it can be used for drawing lines, although the real purpose of this ruler is only for supporting the hands when working on stone, that they may not touch the prepared surface.

If the work-table is made with high pieces at the ends so that the ruler can rest on them without touching the stone, no ruler supports are required. Otherwise one must have these two pieces, a little higher than the stone, so that the ruler may rest on them.

A specially made work-table has another advantage. In the middle there can be a turntable on which the stone rests, so that it can be moved easily into any position, something that is very difficult with large stones without this arrangement.

Music-writing pens are bra.s.s or silver tubes which have the shape of musical notes underneath, and which take up such a quant.i.ty of chemical ink that one can make about twenty notes without re-dipping. That they shall not take up too much ink, a fine wire is fastened in the centre.

These instruments must be very exactly ground and their use demands some skill if the notes are to be uniform.

Instead of this instrument a piece of wood may be used, but this must be inked anew for each note. To avoid dipping too deep, it is best to spread some ink on a little stone and ink the instrument from this. It must be wetted in the beginning, that the ink may be sucked up about three lines high. After that the ink on the stone need merely be touched with it, and this makes the work very uniform. Beginners find this easy to use. But one works more swiftly with the other.

Of the rastrums, there is nothing to say except that they are of steel and very even at the ends so that they touch the stone in all places.

They serve to draw the five lines for music. For making the broad strokes for notes, one can use coa.r.s.e drawing-pens, or coa.r.s.ely cut steel pens; but the best are those adjustable drawing-pens that are made from three blades.

The brush for spatter-work, the wiping-machine, and the dauber will be described in the description of the styles of work for which they are used.

Ink-rollers and b.a.l.l.s are for laying on the printing-color. The latter are made from soft leather, stuffed with horsehair, like the ordinary book-printer's b.a.l.l.s. The former are wooden cylinders with thin handles, of any requisite length and about four to five inches thick. They are wound with two or three thicknesses of woolen cloth and then covered very firmly and evenly with leather. Usually there is used sheep's leather from which the grease has not been entirely removed. Calfskin, worked white, is good and more durable. Dogskin is considered best. Some printers use soft red calfskin, turning the inner side out. The leather must not be st.i.tched with linen but with silk thread, because linen does not take the ink as well as leather and silk do. The leather must be dampened when being drawn over the cylinder.

A fair stock of these rollers is required, because they are liable to become water-soaked during use, when they lose much elasticity and fail to give good service, so that dry ones must be on hand.

It is not well to have movable handles on the rollers, because then they are likely to roll over the stone too lightly and it is not within one's power to lay on the ink thoroughly. To prevent blistering the hands, thick leather covers may be used. Then it is possible to use any desired pressure.

Paper presses are needed both to obtain a uniform dampening of the paper as also to restore the proper flatness to the printed paper. Models are to be seen at the shops of all book-printers and binders.

CHAPTER V

CONCERNING PAPER

Three kinds of paper are used mainly in lithography. They are:--

(_a_) the transparent, oiled or varnished paper; (_b_) underlay or waste paper; and (_c_) the printing-paper.

I

TRANSPARENT PAPER, AND THE TRANSFER OF OUTLINES TO THE STONE

Oiled paper is used for tracing a drawing accurately and then transferring it to the stone either by transferring or by re-tracing it on the stone. It must have the following properties:--

(1) It must not s.m.u.t the original drawing on which it is laid.

Consequently it must be absolutely dry.

(2) It must be very transparent, like gla.s.s, so that the underlying drawing or painting can be seen perfectly.

(3) The ink or lead crayon used for copying must lie on it easily and plainly.

It is at its best if it is easy to work on it with a fine brush, using Chinese ink, or, (if the drawing is to be transferred directly to the stone), with the soft chemical ink described under the caption "Transfer Ink." Generally this can be done without further preparation in the case of most papers made transparent by oiling. Varnished paper, however, which is far more transparent, generally must be well washed with milk and dried again beforehand, that it may take the ink well and permit work with the finest strokes.

(4) Finally, a good tracing-paper must be very fine, pliable, tender and yet not in the least brittle. There is some very transparent varnished paper, but it breaks at the first attempt to bend it, so that it is hard to trace the drawing afterward on stone with the tracing-needle, because nearly every stroke tears the paper and the lines and outlines become coa.r.s.e.

Very good transparent paper may be made as follows:--

Take the finest writing or vellum paper and soak it with nut or poppy oil, mixed with a little sugar of lead to make it dry more readily. When well soaked with oil, dry it a bit between waste paper and hang it up.

Usually it is available in a few days. This paper is cheaper than the paper sold by stationers under the names of straw paper, etc., and about equally transparent. Still more transparent will it be if instead of the oil a varnish cooked from the oils is used. In this also the sugar of lead is an excellent drier. To make the varnish easier to manipulate and more readily penetrative for the paper, it may be thinned down with oil of turpentine. If it is desired to manufacture a greater quant.i.ty of this paper, one sheet is laid on another and painted with varnish. Then the whole ma.s.s is left for some time covered with a stone plate or a board, that the varnish may soak properly and evenly into all the sheets. Afterward the sheets are hung up singly to dry. The more varnish they have, the more transparent will they be; but too much is not good.

Care must be taken that no drops of varnish adhere. It is best to brush the varnish evenly over each sheet before hanging it up.

Silk paper, such as is used in copper-printing to lay between impressions to prevent off-set, is still better for varnis.h.i.+ng because it is finer. Only it must be very even and have no holes. The very greatest fineness of paper is desirable, for the reason that then the strokes made by the needle on the stone are fine and not coa.r.s.e.

Instead of varnish made by boiling down nut or poppy oil, one can use Venetian turpentine, which merely has been thinned down with one half as much oil of turpentine. Such paper generally is dry enough after twenty-four hours. Too large a quant.i.ty must not be made at one time, because it becomes tough and brittle after a while.

Even with the most transparent paper it occurs that certain delicate drawings, and especially color pictures, will not show through sufficiently. Then the drawing must be fastened to a window pane to obtain added illumination. This manner of work is very uncomfortable, however, and the arms hurt one soon, so that it is necessary to stop. It is better to have a tracing-board made with a strong, clear pane of gla.s.s in the centre. Under it is a mirror so adjusted that it reflects light upward through the drawing.

It is understood, of course, that in tracing only the outlines are copied and not every stroke of shading, etc. Although the final work is greatly facilitated by the observation of the utmost care in tracing, the tracing of every little detail will merely make the work involved and perplexing. Practice must show the proper degree of exactness. A very good and skillful artist often needs only a few main outlines, to reproduce the original picture with the greatest accuracy.

Once the drawing has been traced sufficiently, the transfer paper must be coated very lightly and evenly with red chalk. Then it is fastened to the stone with wax and all the lines are traced under moderate pressure with a well-polished needle whose point is not sharp but rounded. Where the needle presses the tracing-paper, the color that is on the other side will take hold of the stone and thus transfer the drawing to it. If the needle is too sharp, it will injure the paper, and often the stone and the etching surface. The color on the paper must be rubbed off very carefully with a soft rag. If it is too thick, it will transfer itself coa.r.s.ely to the stone. The red chalk may be put on the side of the paper that has the drawing on it, or on the reverse. This is decided according as the picture is to be on the stone in the same position as the original or reversed. If the impression is to be like the original, the drawing on the stone must be reversed; therefore in that case the tracing-paper is coated on the same side as the drawing. This side is laid on the stone, and the picture, which shows through, is traced.

In some cases it is good to transfer the drawing from the tracing immediately to the stone without tracing it with the needle. In this case, the paper is not coated with red chalk. The paper is merely laid on the prepared stone, drawing face down, and put through the press. If the drawing has been made with the chemical transfer ink, blackened with lampblack or colored with vermilion according to need, it will transfer itself to the stone. This will occur also in the case of a clean stone prepared for pen drawing if the drawing is made with lead pencil or with red chalk, wet or dry. Even the ordinary ink made from nutgall and vitriol of iron will transfer if it contains a little sugar or gum, but the paper must be well dampened and good pressure must be applied to the press.

In the pen-drawing process, the stone must be cleansed of possible surplus of color after the transfer. This is done by light rubbing with sand. It is not necessary in other processes. Any surplus of color that may have fixed itself to the stone is removed by gentle dusting with a soft brush.

II

WASTE PAPER

This is used partly for cleansing plates, partly and chiefly as underlay in printing.

If sheets are to be printed on both sides, usually a little of the first impression off-sets on the underlay paper, and if it were used again at once, it would off-set on the next impression. Therefore a fresh underlay paper must be used for each impression of the second side.

This must not be coa.r.s.e, for fear of causing unevenness or holes in the leather in the printing-frame or in the so-called sc.r.a.per-wood that makes the impression. A good quant.i.ty of this must be on hand, that fresh paper may always be available while the used paper is drying again. Each sheet that has been used should be hung up at once, and not more than three or four sheets should be hung over each other, to facilitate the drying. A special appliance is needed for this as well as for drying the impressions. A number of slats are fastened to the ceiling, leaving a s.p.a.ce under it of about two feet, and about one foot distant from each other; and the sheets are hung on these with a pole made for the purpose, such as may be seen in any printery.

III

PRINTING-PAPER

Not all kinds of paper are equally good for lithography. On the whole, however, it may be a.s.sumed that this form of printing is very similar to copper-printing and book-printing, and that the paper that is good for these branches is suitable also for the stone, if only it does not contain too many impurities, grains of sand and other substances that make any considerable roughnesses. Such roughnesses, if considerable, have an ill effect not only on the impression, but chiefly on the leather in the printing frame. If the sc.r.a.per is of wood, the leather will suffer less, but there will be caused grooves in the sc.r.a.per that must be planed out again, because otherwise each following impression will show a more or less plain streak. If the sc.r.a.per is of metal, the leather may tear or the stone itself may be injured if the foreign substance in the paper is very hard. Therefore it is well to hold the paper to the light before dampening or printing and to remove any apparent defect of magnitude with a little knife.