Textiles and Clothing Part 7

The fiber may be dyed in a loose or unspun state, as is customary with wool; after it has been spun and is in the form of yarn, as in the case of silk and linen; and when it has been woven to form cloth, as is most commonly the case with cotton.

[Sidenote: Madder Bleach]

The bleaching of cotton involves a number of steps, the most thorough process being called the "madder bleach," in which the cloth is (1) wet out, (2) boiled with lime water, (3) rinsed, (4) treated with acid, (5) rinsed, (6) boiled with soap and alkali, (7) rinsed, (8) treated with bleaching powder solution, (9) rinsed, (10) treated with acid, (11) finally rinsed again. All this is done by machines and hundreds of yards go through the process at a time. The product is a pure white cloth suitable for dyeing light shades and for white goods. When cloth is to be dyed a dark shade the treatment is less elaborate.

[Sidenote: Singeing and Shearing]

If the cloth is to be printed for calicoes, before bleaching it is singed by pa.s.sing through gas flames or over a red hot plate and then sheared in a shearing machine constructed somewhat on the principle of the lawn mower, the cloth being run close to the rapidly revolving knives.

Although cotton is usually dyed in the piece, it may be dyed in the form of yarn, as for ginghams, and sometimes before being woven, in the loose state.

[Sidenote: Mordant Colors]

Cotton is more difficult to dye than wool or silk. Although there are now what are called "direct" cotton colors, the usual process is to first treat the cotton goods with a "mordant"--various salts of aluminum, chromium, iron, tin and copper, fixing these on the fiber by means of tannin or alkali. The mordanted cloth is then entered into the dye bath and boiled for an hour or longer, until the desired shade is obtained or the dye bath exhausted. The salts of aluminum are used as mordants for the lighter shades, the salts of chromium for the medium shades, and iron for the dark shades. In general, chromium mordants give the fastest dyes.

[Sidenote: Aniline Dyes]

The discovery of the so-called aniline dyes has greatly increased the variety of colors available. Although some of the first aniline dyes to be made were not fast to washing or to light and they thus received a bad reputation, they are now to be obtained which compare favorably in fastness with the natural dye stuffs such as cochineal, madder, etc., provided sufficient time and care are given to dyeing. The chief trouble is that in the endeavor to furnish cheap goods, processes are hurried and results are unsatisfactory.

[Sidenote: Home Dyeing]

Home dyeing is practically confined to the use of direct aniline colors.

These are put up in small quant.i.ties and sold in many places. Directions for their use are given on the packages. The chief precautions are to have the goods perfectly clean and thoroughly wet before entering into the dye bath (this is by no means as easy as one might think), and to keep the goods in motion while dyeing so as to prevent unevenness of shade. Wool and silk dyes cannot be used for cotton and linen, nor the reverse. Of course cloth already colored cannot be dyed a lighter shade of the same color and the original shade must be very light to enable one to change the color, say from red to blue, etc. The original color always modifies that of the dye somewhat and it is best to experiment first with a small portion of the dye and cloth. Rather dark shades are apt to be most successful.

[Sidenote: Natural Dyestuffs]

Indigo for blue, madder for Turkey red, logwood with fustic for black, cutch or gambia for browns on cotton are about all the natural dyestuffs which are used to any extent commercially at the present time. The artificial product alizerin, the active principle of madder, has about superseded the natural dyestuff, and artificial indigo is gaining on the natural product.

Linen is bleached and dyed in much the same manner as cotton, although the process is more difficult. The process of bleaching weakens linen more than cotton.

[Sidenote: Dyeing Woolen and Silk]

Woolen and silk may be dyed directly with a great variety of dyes without the addition of a mordant, although they are often mordanted.

Both must be well washed or scoured before dyeing. When white or delicate shades on woolen or silk are desired they are bleached. The bleaching is usually done with sulphurous acid gas, the cloth or yarn being exposed in a damp condition to the fumes of burning sulphur.

Were it not for the expense, hydrogen peroxide would be the ideal bleaching agent for the animal fibers.

PRINTING

A great variety of colored designs are produced on the loom by using different colored warp and filling yarns and different weaves, but in all these the designs are easily made only in somewhat rectangular patterns.

[Sidenote: Block and Machine Printing]

Print goods have doubtless evolved from the decoration of fabrics with the brush. Block printing was first used, the design being engraved in relief on blocks of wood. These are dipped in the colored paste, spread thinly, and applied to successive portions of the cloth by hand. These blocks are now replaced in the printing machine by engraved copper rolls, the design being such that it is repeated once or a number of times in each revolution of the cylinder. There is a printing roll for each color of the design. Sometimes both the background and the design are printed on the cloth, but the more common process is for the design only to be printed on the cloth which may be dyed afterwards. In the paste of the printed design there is some chemical which prevents the portions printed from taking the dye, consequently these remain white or a different color. This is called the "resist" process. Another process is to first dye the cloth and then print on some chemical which, when the calico is steamed, discharges the color. This is called the "discharge" process. Sometimes this weakens the goods in the places where the color has been discharged.

[Sidenote: Fixing the Print]

The color paste used for printing contains both the dye and the mordant.

After the calico has been printed it is steamed to develop and fix the color, washed, sometimes very slightly bleached, to clear the whites, and usually given a sizing of starch or gum, and then pressed and dried by pa.s.sing over slowly revolving, steam-heated drums.

In general print goods are not so fast to washing and to light as those that have been dyed in the regular way, although the better grades are reasonably fast.

Prints are sometimes made in imitation of the more costly gingham or other goods in which the color design is made in the weaving. It is easy to detect the imitation as the design of printed fabrics does not penetrate to the back of the cloth.

[Sidenote: Warp Printing]

Sometimes the warps are printed before the cloth is woven, thus giving very pretty indefinite designs, especially in silk.

FINISHING

[Sidenote: Burling and Mending]

The finishing of woolen and worsted goods has much to do with their appearance. No cloth comes from the loom in a perfect condition, therefore inspection is the first process. Loose threads and knots are carefully cut off by the "burler" and imperfections in the weaving rectified by the "menders." The goods may now be singed and sheared.

[Sidenote: Fulling]

[Sidenote: Flocks]

Woolens, and sometimes worsteds, are next "fulled" or felted by being run round and round in a machine while moistened with soap. The friction of the cloth on itself produces some heat which, with the moisture and soap, causes the goods to shrink in length and width while increasing in thickness. During this process, "flocks" are often added, especially for smooth finished woolen goods. These flocks are fine fibers of wool obtained from the shearing machine or made by cutting up old woolen cloth. They are felted with the fibers of the goods and add weight and firmness.

[Sidenote: Raising the Nap]

After the fulling, the goods is washed to remove the soap, dyed, if desired, and often "speck dyed" with a special dye which colors the bits of burs, remaining in the cloth, but not the wool. The next process is the "gigging" which raises the nap. The cloth is run close to rapidly revolving "teazels" and also may be run through a napping machine. It may be sheared again and then steamed and pressed. This is but a brief outline; there are generally more processes.

Woolen cloth coming from the loom may be so treated in the finishing room as to produce fabrics entirely different in appearance. One of the chief objects of the finishing is to give to the cloth as fine an appearance as possible to attract the buyer. Much of the fine finish disappears through wear, especially with inferior goods made from poor materials. The wearing quality of the goods is primarily dependent upon the strength and quality of the fibers of which it is made, so that the yarn of the filling and the warp should be examined when selecting materials. In general hard twisted yarn will give the better wearing cloth.

FABRICS

The present day shops offer such a great variety of fabrics that only a few of the most important can be mentioned here.

COTTON GOODS

Cotton is cool and heavy, is a non-conductor of heat, crushes easily, but like all vegetable fibers it may be laundered without injury to the fibers. Cotton does not take the darker dyes as well as animal fibers and for this reason it does not combine satisfactorily with wool. As an adulterant it wears shabby and loses its brightness. It is only when cotton does not pretend to be anything else that it is our most useful and durable textile. The readiness with which cotton takes the lighter dyes and improved methods of ginning, spinning, and weaving have made cotton goods superior to any other for summer use.

[Sidenote: Muslin]

Muslin, calico, and gingham must always head the list of cotton goods.

Muslin is coa.r.s.e and fine, bleached, unbleached, and half bleached, twilled or plain weave. Under the head of muslin brought to a high degree of perfection in weave and finish will be found dimity, mull, Indian lawn, organdie, Swiss, and Madras, and a host of others equally beautiful. Madras muslin has a thin transparent ground with a heavily raised pattern woven of a soft, thick thread unlike the ground work.

Waste is used for the pattern. Organdie muslin is soft, opaque, white, or colored, with raised dots of pattern and plain weave. Dimity has a fine cord running with the selvage.

Gingham is a smooth, close cotton usually woven in checks or stripes.

The yarn is dyed before being woven, making the cloth alike on both sides, and the weave is either plain or twilled. Ginghams are also woven of silk and cotton mixed or of silk and ramie.