CHAPTER XV
STENCILS AND STENCILLING
DIRECT APPLICATION OF COLORS
=History.=—During the last few years a great deal of attention has been paid to the manufacture and use of stencils for decorating textiles, not only by craft workers of different kinds, but also by art teachers in private and public schools.
The art is not a modern one, even in this country, for I have seen and worked with a series of very interesting stencils cut in brass, which were owned in Philadelphia by the famous old physician, Dr. Benjamin Rush, over a hundred years ago, and were used in his family for marking linen, as well as for decorating homespuns and paper.
The real home of the art, however, is Japan, where, for over three hundred years, stencils have been in common use, largely replacing the wood blocks used in other countries, for decorating the common cotton goods, towels, head coverings, and the like of the lower classes, and also for ornamenting, where embroidery was not desired, the beautiful silks and satins of the wealthy.
Ever since Japan has been opened to the world travelers have been telling wonderful stories of the great skill of the natives in this beautiful art. According to some writers, as soon as a child is born it is given a nickname, and with it, as a sort of totem, a design—a flower, for instance, for a girl—a tree or an animal for a boy—and the like. This design, worked out carefully, after due criticism from all the family elders, is drawn on brown paper and then carefully cut out with a sharp knife by some member or friend of the family. And this stencil is then sent to the local dyer to be used in dyeing the infant’s clothes. This same design, or a modification of it, is attached to the person through life, as his or her own private pattern, and whenever new clothes are needed they are dyed after this same pattern.
=Japanese Stencils.=—_Paper._—It is a common fact that the very first thing noticeable about Japanese stencils, whether brought from some dyehouse in the interior, or whether made more or less mechanically, for the American market, to be sold to students or craftsmen, is the quality of the paper. It is thin, hardly heavier than ordinary writing paper, but exceedingly tough and strong, and cuts very easily, without tearing. It can occasionally be obtained from importers in sheets, and even better qualities can be secured, from among a mass of old stencils, by finding some which have been only partially cut or used up, and carefully cutting out from them the unused portions where these are large enough for the purpose.
[Illustration: FIG. 13—JAPANESE STENCIL KNIFE]
[Illustration: FIG. 14—JAPANESE STENCIL BRUSHES]
_Knives._—In cutting stencil designs our American practice is to use a sharp penknife, or a Sloyd knife, or, as happens occasionally with some of my friends with amiable professional husbands, a surgeon’s scalpel. None of these, however, compare for neatness, accuracy, and ease and comfort of manipulation, with the very simple but extremely effective little Japanese knives shown in Fig. 13. The knife blade, of very highly tempered steel, is two or three inches long and fits between two flattened plates of wood, tied together tightly at the bottom but springing apart a little toward the top, as a handle. This little spring of the handle is most satisfactory. And as the blade, which is triangular and sharply pointed, is worn away gradually by the constant grinding and sharpening it must receive, the steel can be pushed forward from between the two halves of the handle, until the proper length is reached.
_Cutting._—The Japanese draw their designs on paper with India ink, and then, with incredible swiftness and accuracy, the lines are cut, by pushing the knife blade, held with the back downwards, away from the workman, and through the paper which is placed flat on a piece of wood or small tray, with depressions in it half an inch or so deep, to avoid the danger and bother of running the knife point into the wood.
=American Practice.=—Our way differs somewhat. The design is usually drawn on a separate piece of white paper, and filled in—in black—with India ink. This is then placed underneath the stencil paper which, especially if it has been oiled or paraffined, is translucent enough to show the pattern through, so that the outline can be drawn with a sharp pencil. The outline can also be made by tracing the design down on the stencil paper with the help of a piece of carbon copying paper. This is laid between the design and the stencil paper and then the outline of the design is carefully traced with a sharp-pointed pencil. From these outlines it is easy, with a sharp stencil knife, to cut out the design, although it is customary with us to cut toward the body with the point of the knife down, upon a piece of blotting paper or soft wood so as not to dull it too rapidly.
_Ties and Stops._—When stencilling is taught in America great pains are taken to show how the pattern must be planned and cut out, so as to have plenty of “ties” or “stops” in the right places, so as to hold the stencil together. For instance, in making a stencil of a large capital O, the student should be warned that, if the paper was cut all the way around, it would leave a big hole; for the central piece, which would form the centre of the finished letter, would drop out, and could not be kept in place. Accordingly, the stencil would have to be cut carefully, leaving at least two “bridges” or little “tie pieces” of paper, one probably at the top, and the other at the bottom of the O, these being the narrowest points, which would hold the centre in place, and thus complete the figure. Indeed, if these little “steps” or “bridges” of paper should be left out, or become torn or broken, the stencil would be useless. But a situation like this has little or no terror for the Japanese, at any rate when working for their home trade. Their stencils cut for the American market while always interesting, and often charming, are cut, as ours are, from one piece of paper, with stops in the exposed places. But the stencils that have been used, or cut for use, over there, show a very different state of affairs. All of the large, handsome ones, and a large proportion of the smaller, less artistic, and less valuable ones are made, with almost inconceivable skill and patience, in duplicate. And the two parts are afterwards pasted together with absolute accuracy, but with a layer of fine hair, supposedly human hair, between them. These hairs, laid irregularly but evenly, make a sort of network which ties together all portions of the stencil, no matter how disconnected with the rest, or, as we would say, “in the air,” it might be.
So, too, they are in the habit of sewing in, with the finest of hair or of single threads of fine silk, loose pieces or broken pieces, and thus holding them in shape.
It is interesting to study some of them closely and see how neatly this tying is done and how little the time of these unknown workmen must be valued at. For apart from the large picture stencils which, of course, would be worth taking a great deal of pains with, some of the simplest and most ordinary of their native stencils are not only cut but tied in, with extraordinary skill. One of these, valued here at but a few cents, consisted of a background of small figures in shape and size very much like a capital O of the type of this page. The stencil measures some eighteen by ten inches, and there must be between fifteen hundred and two thousand of these O figures on it. Some few of these are now imperfect, but with the exception of a dozen or two, every single one of all these has had the centre cut out, and then sewed into place again, from the sides, so as to be in the exact centre, without a single “stop” or “tie” on the whole paper.
_Brushes._—With stencils so very delicately made, it is evident that our crude American style of rubbing in the color, with heavy hands and stiff bristle brushes, would not be much of a success! About one good rub with a brush like that, and every hair in sight would be torn and broken, and what was a minute before a work of art would be a torn mass of brown paper.
Whether any of our American craftsmen have light enough hands to use, successfully, a fine Japanese stencil is doubtful. Personally, I could no more stencil six inches with any of them without ruining it or making a mess of the cloth than I could in a year cut, without tearing, six square inches of any one of a score of cheap and ordinary Japanese stencils which I own, either presented to me or sold at a very low price, as being really too insignificant in value to amount to anything.
But at any rate, the Japanese do not use a stiff bristle brush. Their brushes, in general, are of two sorts, as shown in Fig. 14. One is a sort of pad, often quite large, five or six inches in diameter, made of rabbit’s fur, tightly bound together with cord or wire, and with a bundle of small sticks spreading out to enclose the pad, and drawn together and tied above, at the upper end, in a sort of pyramid.
[Illustration: FIG. 15—JAPANESE STENCIL, SHOWING HOLES PUNCHED BY HAND TOOL]
[Illustration: FIG. 16—JAPANESE STENCIL, EXACT SIZE, SHOWING USE OF STOPS]
[Illustration: FIG. 17—JAPANESE STENCIL, EXACT SIZE, SHOWING USE OF SEWING INSTEAD OF STOPS]
The other variety is a true brush, of a more ordinary shape, like a flat paint brush, but also made of the very softest and finest, most velvety hairs imaginable, laid extremely close together, and compressed tightly between the two halves of the handle. These can be obtained occasionally from the dealers at reasonable prices, and are delightful to work with. Only, being meant for the soft, light touches of their native workmen, they do not last long when rubbed down on the cloth as is our practise. Their life is considerably increased by pouring some molten beeswax into the back of both goods and brushes with a batik pot, or Tjanting, which prevents the fine hairs from pulling out until the brush is all worn to pieces.
_The Care of Stencils._—A word may here be said about taking care of stencils, after they have been cut or purchased. They should always be used on one side, and carefully wiped off with a damp cloth, directly after using. They should always be kept flat, never folded. And, when using them, it must always be remembered that the ties or bridges are the weak spots, and that breaking or tearing them, as a rule, will spoil the stencil. It is, of course, possible to mend them by sewing, or sometimes by patching with tape. But this is always troublesome, and with well paraffined stencils is rarely satisfactory.
_The Different Methods of Using Stencils._—In this country, so far as can be ascertained, the common way in which stencils have been used is by brushing through them, on to the cloth, oil paints thinned with turpentine or gasoline. As previously explained, in the chapter on feather dyeing, this is not very satisfactory. For when paint is sufficiently thick to adhere well to the cloth, it is apt to look stiff and shiny. And when it is applied so thin that the structure of the cloth shows through, it is, as a rule, not fast to washing or even to rubbing. Various varnishes are on the market which help considerably to make the paint fast, but even then the results are not nearly so durable as when the proper dyestuffs are used.
The Japanese practice is exclusively with dyes, and they have worked out processes which are perfectly satisfactory, so that their simple, cheap, stencilled towels can stand washing indefinitely without loss of color. And by the use of modern dyestuffs there is no insuperable obstacle to our doing just as well as they.
The use of stencils gives an excellent opportunity to illustrate the three general methods of coloring fabrics, which, as mentioned in the last chapter, consist of:
Direct application of color. Resist, and Discharge.
The last two of these will be reserved for the next chapter.
[Illustration: FIG. 18—JAPANESE STENCILS, EXACT SIZE, SHOWING USE OF BOTH STOPS AND NET]
=Direct Application of Color.=—In this intricate work it will generally be found almost a necessity to apply colors through a stencil in the form of a paste, for when the coloring liquid is thin it is very apt to run under the edges of the paper and spoil the design. It is best to thicken it with a little “gum dragon,” a carefully prepared paste of gum tragacanth, to which the coloring matter, and any reagents that are needed, can be added. The nature of the reagents and the class of dyestuffs used depends, of course, upon the kind of material to be stencilled.
=(a) Leather.=—While not very often used, students interested in leather work will find a carefully designed and neatly cut stencil a most useful medium for obtaining interesting and beautiful effects. The leather, whether bark- or alum-tanned, should be carefully dampened, and then stencilled with a paste containing Basic colors dissolved with a drop of acetic acid. On drying, the leather should be finished as usual. The Acid colors are not nearly so satisfactory for stencilling, although, as already mentioned, they are often advantageous for dyeing, rather than staining, leather fast colors.
=(b) Silk.=—Silk may easily be stencilled provided the pattern is not expected to be fast to washing.
1. _Acid Colors._—These dyes, mixed with a few drops of formic or acetic acid, will color it well, but to make the dyestuff penetrate it is advisable to steam the goods. This can be done with a teakettle provided with a wing tip for the spout, made of tin, or by heating a flatiron or iron plate very hot, and pressing the stencilled goods back down against it, with a damp cloth in between. The hot steam thus produced, passing through the goods, melts the paste and drives the color down into the fibres and sets it there, so that, later, the stencilled goods will stand light rinsing in lukewarm soap and water without running.
2. _Salt Colors._—Faster results can be obtained, on silk, with a paste containing salt dyes, with a drop or two of acetic acid, provided the silk is thoroughly steamed afterwards.
3. _Basic Colors._—Basic dyes may be used on silk as on wool, leather, or any other animal fibres for direct application, the dyestuff dissolved with a drop of acetic acid, being added to the paste, and then brushed in and, preferably, lightly steamed to sink the paste down into the fibres. These dyes, however, with but few exceptions, are not fast to light, and applied in this way are not fast, either, to washing. By adding some reagents to the paste, however, a Basic stencil paste can be formed which gives colors on silk which will stand active scrubbing excellently.
The Basic Stencil Paste is prepared by mixing with the paste a solution containing the Basic color, dissolved in acetic acid, and also containing a considerable quantity of tannic acid. As long as there is free acetic acid present in this mixture the color remains in solution, but directly the acid is driven off, an insoluble compound remains, formed by the combination of the tannic acid with the color base. This happens on steaming, and the insolubility of the product is still further increased by passing it through a weak bath or wetting it with a weak solution (half a teaspoonful to the quart) of tartar emetic.
Accordingly, to use this stencil paste on silk or, indeed, on cotton, the slightly dampened goods are stencilled with the paste, thinned if desired with water and a little acetic acid. Then directly they are dry enough so as not to run they are well steamed, then the gum rinsed off with a little warm water, and the goods moistened with the tartar emetic. After this they can be washed with soap with little or no danger of running.
=(c) Wool.=—Wool is rarely stencilled, although stencil patterns can be produced very well on it by using acid colors with a little oxalate of ammonia (about the same amount as the dyestuff), dissolved in a drop or two of water, and thickened with a little gum tragacanth. When this paste is applied with a brush, and then dried, the result is not fast at all, merely a distinct stain; but if steamed at once the oxalate of ammonia decomposes, leaving oxalic acid, which, combining with the color and melting down with it in the fibres, makes the dyestuff adhere quite firmly.
=(d) Cotton and Linen.=—It is much more difficult to stencil satisfactorily on vegetable goods, such as cotton and linen, than on the animal fibres above mentioned, because they are expected to stand very much more severe treatment. The fastness to washing needed for a handsome silk scarf is far less than for a cotton shirtwaist, or linen table-cover, and unless the results on the latter are at least as fast as the average calico print, the result is considered a failure.
There are three classes of dyes which can be used in this connection, the Basic dyes, the Sulphur dyes, and the Indigo or Vat dyes. The Basic stencil pastes have just been described, in connection with silk stencilling, and when carefully used they will give very fair results on cotton, and even on linen, provided it is free from dressing, and is not too coarse and thick. It is hardly worth while trying to fasten Basic dyes, by hand stencilling, upon such materials as heavy, coarse Russian crash, for instance, such as friends and students have frequently brought in to experiment with. But for light, thin materials, and especially for mercerized goods, poplins and the like, it is possible, with a little practice, to get effects that are fast to ordinary washing.
On the other hand, this method of stencilling has certain disadvantages. It is rather complicated, needing the use of a fixing bath of tartar emetic, a very active poison, by the way, although more uncomfortable than actually dangerous when taken by mistake in one dose, because of the severe vomiting it produces almost immediately. And then, too, the results at best are not really fast to light, and in the case of light pinks and yellows are distinctly fugitive.
_Vat Color Stencil Pastes._—Many experiments have been made in our laboratory to work out a satisfactory stencil paste, so that Indigo and other Vat dyes could be applied, simply and easily, with no more difficulty than the usual one of brushing the paste in carefully, and then steaming as soon as possible. In these stencil pastes the Indigo and the other Vat dyes are reduced with the aid of caustic alkali and hydrosulphite before being mixed with the paste, and some special precautions are taken to prevent, as far as possible, the oxidation of the dyestuff before it gets well into the fibre. But, as the ordinary hydrosulphite is apt to decompose on standing, especially when it is wet, it is always best, just before using, to mix well with the paste a little fresh reducing agent, dissolved in a drop of hot water. The reducing agent that should be used for this purpose is not the ordinary hydrosulphite of soda, used for vat dyeing, but a compound of sodium hydrosulphite, “Stencil Salt,” which has the property of keeping better than the other, and also of not acting as a reducing agent until it is heated. This, then, is stirred into the Vat color stencil paste, just before using, and then, when the goods are steamed, the heat and moisture combined will enable it to reduce the color, which will be carried into the fibres in a reduced and dissolved condition. After steaming well for five minutes the color should be developed by a bath in hot soapsuds, after which the goods should be rinsed and dried. With care this process will give very satisfactory results, perfectly fast to both light and washing, after the first loose color has been washed off.
The indigo stencil paste, as prepared, will keep well reduced for quite a long time, and it is frequently quite unnecessary to add any fresh reducing agent to it. If, when taken from the tube or bottle, it looks yellow or yellowish green, it can be applied at once to the cloth, and, if steamed just as soon as possible, it will generally penetrate quite satisfactorily. With the other colors of the series, however, it is hard to tell by the color whether they are reduced or not, and hence the fresh reducing agent, Stencil Salt, should always be added to them. The cloth for stencilling with these pastes, as with the Basic pastes, should not be too thick or heavy, and must be washed quite free from dressing, or the result will not be satisfactory. It should also be slightly dampened, if only by holding over boiling water for a moment or two, so as to help the color to penetrate.
_Sulphur Stencil Paste._—We have also found very satisfactory results from pastes made with one of the Sulphur colors, dissolved in a little sodium sulphide and sodium carbonate, and stiffened with a little gum. The presence of a reducing agent helps to keep the color reduced; and, when quickly applied and rapidly steamed, the colors will sink into the fibre and adhere firmly.
The chief drawback with these pastes is the lack of a good red.
=Black Stencil Paste.=—So far as can be learned, the Japanese use for their stencilling an Indigo paste made on the same general principles as the one just described. Besides this, which is a very favorite color of theirs, they use a red and also a very full black dye, both of which are fast to washing and to light.
What the composition of these last pastes may be it is hard to tell. In our laboratory we have made careful experiments on the subject of stencilling black, and have worked out a method that we consider satisfactory by the use of a modification of the well-known Aniline Black process.
[Illustration: FIG. 19—LARGE AND HANDSOME JAPANESE STENCIL, SHOWING USE OF NET]
_Aniline Black._—It was noticed, early in the history of dyestuffs, that if aniline was mixed with strong oxidizing agents, and carefully heated, it would undergo a series of color changes resulting, finally, in black. This color, so-called “Aniline Black,” was at one time manufactured and used for a black pigment; but it was soon recognized that its real value would only be developed when it could be formed, in the fibre itself, by the oxidation of aniline or some compound of aniline upon the fibres. After many years of experimenting this problem was solved, and for fifteen or twenty years the blacks most used on cotton and linen by the calico printers, as well as by the dyers, have been one or another of the forms of Aniline Black.
The principle on which these processes are based is as follows: The aniline, usually in the form of aniline salt (aniline hydrochloride), is mixed with an oxidizing agent like chlorate of soda, and also with a small amount of a third substance which, on steaming, acts as a carrier of oxygen between the aniline and the chlorate. This substance, often called a catalytic agent, because at the end of the operation it remains unchanged, although it has accomplished a large amount of work, may be one of a number of compounds as, for instance, a salt of the metal vanadium, prussiate of potash, a salt of copper, etc., each one having special advantages and disadvantages of its own.
Now, almost any printing paste properly composed so as to give a good clear Aniline Black on steaming, (the formulæ can be obtained from any good book on calico printing, or from any competent dyeing chemist), will generally work fairly well as a stencil paste—as long as it is fresh. But even when kept from the air as far as possible, in a tight tube, it decomposes on standing and becomes very unsatisfactory. Besides this, there is always a difficulty with these regular pastes on account of the irregular and uncertain steaming process that can be used by the average craftsman. In a calico print works, the temperature of the steam chest, the proportion of steam in it, and the length of passage of the cloth through it, are all accurately determined, and kept at the exact points necessary for the best results with any given formula. But with irregular steaming, unless very great care is taken with the formula, there is always a danger of “tendering” and burning the fibre, if too much oxidizing agent is present, or of not developing a full black, but a dark green color, if the oxidizing agent is not active enough.
We have, after a great deal of experimenting, worked out a formula which, with reasonable care in steaming, will give a good full black, absolutely fast to light and washing, upon cotton, linen, and silk, without any tendering of the cloth. And, by dividing up the component parts into two separate pastes, which are kept in separate tubes or bottles, and are mixed together only when about to be used, we have gone far to solve the important problem of keeping.
The use of this Black stencil paste is very simple. It comes in two tubes or bottles marked A and B.
When the cloth, free from dressing and slightly dampened, is all ready, equal amounts are taken from each of the two tubes, and mixed together in a watch-glass or small glass or porcelain dish with, if necessary, a drop of water to soften them if they have dried up at all. This mixed paste is then brushed on to, and into, the cloth, and, as soon as dry, is steamed as before described. The black color will develop almost immediately, and, after a few minutes’ steaming, will be found fast to hard washing as well as to light.