Batik and other pattern dyeing

by Walter Davis Baker; Ida Strawn Baker

ALL-OVER DYEING

THE simplest process of dyeing a fabric consists in submerging it in a solution of dye, known as a “dye-bath,” and allowing it to extract or exhaust the color from the bath. It is necessary that there be an attraction or affinity between the fiber of the fabric and the dye in solution. All parts of the fabric must be given equal opportunity to extract the dye in order that a uniform color or “level” dyeing be obtained.

To accomplish this end experience has found that a few simple things must be observed. These have to do with, (1) the preparation of the fabric for dyeing, (2) the making of the dye-bath, (3) the handling of the fabric while in the dye-bath, and (4) the handling of the fabric after the dyeing.

1. The Preparation of the Fabric. The fabric must be clean. A spot of grease or other soil allows that part of the fabric less opportunity to extract color from the dye-bath, with the result that the dyeing is not level. Thorough washing with soap and warm water followed by a good rinsing will remove most spots. The methods of the dry cleaner will be necessary for others.

All sizing must be removed. Sizing consists of substances such as clay, flour, starch, gum, oil, tallow, soap, etc., put into the fiber, either before or after weaving, for the purpose of giving weight, body, strength, stiffness, softness, finish, or other desired quality. Some sizing prevents the extraction of color from the dye-bath. In other cases the sizing itself absorbs a large share of the color, and later when the sizing is removed by washing this color goes with it. Vigorous washing with soap and hot water, followed by rinsing, will remove most sizing. A fabric which suffers injury by the removal of its sizing is not suitable for dyeing.

Previously dyed fabrics are often uneven in color due to spotting and fading. Level dyeing cannot be done over such color. The practice of the professional dyer is to remove or level this color before attempting further dyeing. This often calls for skill beyond that of the inexperienced worker. Sometimes prolonged boiling in strong soap suds will accomplish this. Many colors will also yield to hot hydrosulphite solution followed by a good rinsing.

Of course where goods have been previously colored there are limitations as to the colors that may be obtained by additional dyeing. For example, blue goods cannot, without the removal of the blue color, be dyed yellow but may be dyed green or purple or a deeper blue. Yellow goods cannot be dyed pink, but may be dyed orange, green, brown or black. This will be discussed more fully later.

Some fibers are hard and harsh and resistant, like crash and most new cotton cloth. This is due to the presence of gums, resins, waxes and other impurities, substances which either attract dyes or else prevent their taking the fiber. It is not possible to dye such goods successfully without first rendering the fibers soft and absorbent. This may be accomplished by prolonged boiling in washing soda. Repeated washing and exposure to air will also do it, hence old cotton usually dyes well. Technically there are elaborate and carefully carried out chemical processes of preparing cotton cloth for dyeing, and entire mills are busy doing this one thing.

The Javanese and other Oriental peoples purchase cotton cloth from Europe and treat it for many days, alternately soaking in oil and boiling in lye from ashes, then exposing to the hot sun. This process is repeated until the cloth is soft and absorbent and suitable to receive color decoration.

The cloth should always be thoroughly wet before putting it into the dye-bath. This should be done in water of the same temperature as the dye-bath.

It may be briefly mentioned here that a fabric must sometimes be given a treatment with some chemical, called a mordant, before it will exhaust certain dyes from the bath and be properly dyed.

2. The Making of the Dye-Bath. For simple dyeing, as mentioned at the beginning of this chapter, we must observe the following things:

The dye-bath must be sufficient in quantity to cover the goods well and to permit of their being worked thoroughly during the process of dyeing.

For the “dye-vat,” or container for the dye-bath, use preferably a large graniteware pan or stone jar. Metal dishes, especially iron, are sometimes injurious. Professional dyers often use vats of copper, brass or wood.

Soft water is preferable, and it should be free of sediment. The presence of iron in water is most injurious as it dulls, or “saddens,” the shade of most colors. A hard water containing lime should be purified or softened. Lime sometimes causes uneven dyeing.

The dye must be completely dissolved in the water. If specks of undissolved dye are present there will be a spotted uneven dyeing. It is best to dissolve the dye in a small amount of water in a separate dish and then strain it. This should be added to the dye-bath a portion at a time during the dyeing. The reason for this will appear later.

The temperature of the dye-bath has much to do with the dyeing. There is no general rule applicable to all dyes. Each dye is usually accompanied by directions as to the temperature to be used. In general it may be said that all dyes work better in warm or hot solution. Some dyes require prolonged boiling; in other cases boiling is positively injurious to the dye. Sometimes a definite temperature below the boiling point must be maintained. Sometimes the temperature is raised or lowered during the dyeing. In all cases the temperature should be kept the same in the different parts of the bath, otherwise the dyeing will be uneven.

Many dyes, while most successful at high temperature, work very well in moderately warm, or even cold solution. This is of very great advantage in pattern dyeing, as in batik work, where the wax forbids a high temperature.

The composition of the dye-bath is not often as simple as we have indicated. Usually the dyer adds one or more other chemicals to assist in dissolving the dye, to control the rate of absorption of the dye by the fabric, or for some other purpose.

Some of the finest dyeing is done in baths so complex and with operations so exacting in care that only the trained professional with his elaborate equipment is able to undertake it.

3. The Handling of the Fabric in the Dye-Bath. Since all parts of the fabric must have equal opportunity to be dyed, in order that a level dyeing be obtained, it is absolutely necessary that the goods be worked as long as they remain in the dye-bath. This working must be thorough and continuous without interruption. This cannot be emphasized too much.

Let us think what happens if this rule is not heeded and the goods stand a few minutes in the bath. Some parts of the fabric will lie inside the folds of other parts and, having access to only a small part of the dye-bath, will soon exhaust all of the dye available, a condition known as “local exhaustion.” Meanwhile other parts of the fabric more favorably situated will continue to absorb dye. More uneven dyeing in schools and homes is due perhaps to this cause than to any other.

Constant working of the goods keeps the dye that yet remains in solution uniformly distributed in the bath so that all parts of the fabric are absorbing dye alike. It also maintains what is equally essential to level dyeing, a uniform temperature in all parts of the bath.

It is to minimize the danger of uneven dyeing due to this local exhaustion that the dye-bath must be made of sufficient volume to cover the goods well. The goods must be moved about in the bath with the greatest freedom.

It is for the same reason, especially when the affinity between fiber and color is very great, that the dye is added a small portion at a time. The goods after being treated with part of the dye are lifted out of the bath, a new portion of dye quickly added and stirred, and the dyeing operation renewed. This is repeated until the desired shade is obtained.

The beginner is apt to think that to get a full color requires a concentrated dye-bath. Experience will teach him that, when the dyes are properly chosen for his fabric, a full color is obtained better by a longer treatment in a dilute bath, with additions of dye as mentioned above. In this way nearly if not all of the color put into the bath is absorbed by the cloth. This serves for economy of color, makes observation and control of the process easier, simplifies the problem of rinsing, and improves the quality of the dyeing. It is the only way dyeing to shade can be accomplished.

A slow dyeing is generally more level and successful in every way. In cases where the fiber absorbs the color greedily the dyer sometimes puts other ingredients called “assistants” into the bath to retard this absorption.

Frequently the craftsman does shaded dyeing, such as a scarf with deep blue ends grading to a light blue center. The following directions will accomplish this: Hold the scarf in the middle with one hand, dip the ends into the dye-bath and work them thoroughly with the other hand. Then lower the scarf into the bath very gradually without interrupting the working. If a half hour is taken to lower the scarf the ends will be in the bath perhaps thirty-five minutes, the center five minutes, and besides, before the center is dyed most of the color will have been exhausted from the bath.

4. The Handling of the Fabric After the Dyeing. The usual procedure after dyeing is a thorough rinsing to remove all surplus dye and chemicals. The importance of this will be appreciated from the following considerations:

If not removed many chemicals which have been used as assistants, becoming more concentrated as the goods dry, act injuriously on the dye or the fiber. Likewise any unused color will continue to dye the goods and of course unevenly. It is clearly essential that the rinsing be done immediately upon removal of the goods from the bath. The directions sometimes call for washing in soap and water after dyeing.

The excess of rinse water should be removed and the goods dried as rapidly as possible. Usually there is no objection to wringing. A fabric should never be allowed to hang and drain dry, as the dyeing is liable to become uneven in streaks, especially when the dye used is one given to run or “bleed,” or in any case where the rinsing has not been absolutely thorough. The craftsman in dyeing a small piece frequently puts it between towels or newspapers to absorb the excess water and then shakes it until dry. This is to be commended. The technical dyer has suitable machinery to accomplish this work.

To dry a batik piece, where the wax forbids wringing or rough handling in any way, spread the piece carefully on towels or newspapers, cover with more towels or papers to remove the excess water, then shake very gently until dry, or hang on a waxed line.

At no time during the process of dyeing should the goods be allowed to remain in contact with other absorbent surfaces, such as boards, paper, cloth, clothes-line, grass, etc. These are apt to absorb color away from the goods and leave faded streaks or spots. A clothes-line used for this purpose should be waxed to make it non-absorbent.