Textiles and Clothing

by Kate Heintz Watson

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.

Singeing and Shearing

If the cloth is to be printed for calicoes, before bleaching it is singed by passing 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.

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.

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.

Home Dyeing

Home dyeing is practically confined to the use of direct aniline colors. These are put up in small quantities 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.