The cloth is dyed by means of passing over a roller into a dye vat. Small pieces or “swatches” are taken from the ends of the fabric, and compared with the pattern. For it must be remembered that no two lots of crude dyes are of equal strength, and the wools and cottons of different growths and seasons vary greatly, so that the use of a fixed quantity of dye to a given amount of goods will not always give the exact shade. In comparing a sample with the pattern the two are placed side by side below the eyes (reflected light), and then held up to the light and the eye directed along the surface. A judgment must be formed quickly, as a prolonged gaze fatigues the eye and renders it unable to perceive fine shades of difference.
DYE ROOM
1. Dye tub or vat containing dyestuffs.
2. Rolls or cylinders upon which cloth is wound.
3. Cloth leaving dye tub—being wound upon No. 2 cylinder.
Cross Dyed. Cross-dyed goods may be described as fabrics woven with black or colored cotton warps and wool or worsted filling and afterwards dyed in the piece. Since cotton has not the same attraction for dyestuffs as wool it is a difficult task to dye a fabric woven with cotton and wool so that both fibers will be identical in depth of color, tone, and brightness. In some cases it is possible to dye a mixed fabric at a single operation, but the usual process is to dye the wool in yarn state and then dye the warp a color as near the color of the wool as possible. In the weaving operation the wool is thrown to the surface. In another method the warp is dyed and woven with a white wool or worsted filling, and dyed in the piece with a dyestuff that will not affect the cotton. In this way the cotton does not take the wool dye, but retains its original color. This class of work is generally used in mohair, alpaca, and luster fabrics, because the natural brilliancy of the luster wool, alpaca, or mohair in the filling is not impaired as would be the case if the cotton in the goods were subjected to a cotton-dye bath after being woven. The principal cloths in this classification are cotton, warp figured melroses, Florentines, glacés, brilliantines, lusters, alpacas, and mohairs; rainproof cloths, and fancy waistings, and in these may be found the same great variety of weaves and patterns that is to be found in the piece-dyed goods already described.
Yarn Dyed. Yarn-dyed goods differ from those previously described in that they are made of yarns that are dyed before being woven, or yarns spun from dyed wool. Wool may be dyed in the raw state (fleece), slubbing, or yarn. Fleece dyeing is preferable for goods intended to stand friction, and that in spite of wear and tear must preserve their color. It is preferred for dark colored goods where much friction is to be encountered, but is seldom used for light colors, since these would be soiled during subsequent processes of manufacture. In this case every fiber is colored uniformly all over. The yarn from this wool and the cloth woven from it are dyed through and through and do not become grayish or whitish by wear and tear.
Slubbing dyeing is preferred to yarn dyeing, for the dyestuff penetrates the loosely twisted roving, and if unevenly dyed, the subsequent operations equalize most thoroughly the irregularities in color.
Yarn dyeing is especially applicable to checks, plaids, and suitings, and in their manufacture the drop box loom (a loom with two or more shuttles) is used. Goods manufactured under this classification include cotton warp checks and mixtures; all wool homespuns, mixture coatings and suitings, storm skirtings, rainproof cloths. These goods are made in a great variety of weaves, the effect in each being secured by the color and the weave.
Piece-dyed fabrics may be distinguished from yarn-dyed fabrics by unraveling threads of each kind. In the case of yarn-dyed fabrics the dyestuff has penetrated through the yarn, while in the case of piece-dyed fabrics the dyestuff has no chance to penetrate as completely as the yarn-dyed fabric.
Textile Printing. Printed fabrics such as print cloths can generally be distinguished by observing the back side of the cloth. If the figure or pattern on the face of the cloth does not penetrate through to the back but only shows the outline, the fabric has been printed. Fabrics are printed by coming into contact with rotating rollers on which the pattern is engraved.