National Clothesline

enim is a cotton twill yarn weave colored with a blue indigo dye and woven lengthwise with natural white yarn. That is why denim is blue on top and white underneath. The look of the denim can be a deep color or a faded and worn look created by stone, acid or sand washing techniques used in manufacture. Denim may be napped, printed, or trimmed with ornaments and leather.

Denim denotes fashion and, according to the Cotton Institute, denim is the single highest cotton consuming fabric in the world. The fashion of denim is varied and designers now experiment with the rise of the denim, which is the measurement from the crotch to the top of the waistband.

Some manufacturers create a denim look by piece dyeing and surface dyeing with colors other than the traditional blue.

Although denims are usually cotton, they can be blended with polyester for wrinkle resistance and spandex for stretch.

Denims are used for sportswear, for dress up and casual wear for all types of men’s, women’s and children’s clothing.

Denim is derived from the French word “de nimes,” which means cloth that originated in the French city of Nimes.

Fabric problems

The dye stability and fabric strength of denim varies widely. Crocking may result because the traditional blue indigo dye, although it is a vat dye, has poor affinity for cotton yarns. In dyeing

denim, a chemical process is used which both reduces and oxidizes the dye. A careful balance and proper application of chemicals will insure satisfactory dyeing.

When the dye is poorly applied, friction and mechanical action in normal wear or in routine drycleaning and spotting will result in crocking. Color change may result if the dye used is solvent soluble or water soluble. Many denims are dyed with colors other than the traditional blue and some shades are obtained by combining different colors.

Shrinkage may be a problem because many denims are not pre-shrunk. Shrinkage of 2 percent or less will usually not adversely affect the fit of the garment. Excessive shrinkage of more than 2 percent may be acceptable for work or rough wear but is unacceptable for dress wear.

Mysterious holes

Holes in denim fabric may occur and often cannot be explained.

1. The spinning process used to produce yarn requires control and a selection of fibers with the proper strength and length. Yarns with low tensile strength and poor resistance to abrasion are subject to holes from friction and mechanical action in normal wear.

2. Stone washing. This process is used to give denim fabrics a washed out look by tumbling them with pumice stone chips. This process weakens the fabric and yarn which becomes apparent after the mechanical action of cleaning.

3. Acid wash. The denim may be given a further washed out look by using a bleaching agent. The process is often combined with stone washing.

If the bleaching agents are not properly rinsed or neutralized they will chemically weaken the fabric. The bleach is accelerated by moisture in the atmosphere and the heat used in cleaning.

4. Acid damage will affect cotton, which is the most widely used fiber in denim. The strong acid in batteries will weaken the fabric, which is usually not noticeable before drycleaning. The heat and mechanical action of drycleaning will reveal the damage caused by the acid.

Inspection

When accepting denim sportswear or dress wear, examine the garment for dye crocking especially in areas subject to friction and abrasion such as cuffs, hem, collar, sleeves and pockets.

If the garment requires excessive mechanical action for stain removal inform the customer of possible dye loss due to crocking. Such stains may be paint, oil and ink.

Drycleaning

To avoid color loss on dark or deep colored denims turn inside out and run in a short drycleaning cycle. If denim garments are trimmed with suede, plastic, lace or beads the trimming will determine the load classification.

Spotting

Limit mechanical action when brushing or tamping to avoid dye crocking. Tamping is safer than brushing. Spot on the opposite side of the fabric when possible. Apply lubricants and allow time for penetration which will soften the stain and reduce the amount of the mechanical action needed.

Wetcleaning

To process denim in wetcleaning you should determine the look and feel of the fabric you want to achieve. Some customers want a stiff feel and hard press while others want a soft look and feel.

1. Soft feel. Turn the garment inside out to prevent color loss and wetclean in warm water with a cationic detergent and a softening agent. Dry in a dryer until 100 percent dry and use minimum pressure when finishing.

2. Stiff feel. Turn the garment inside out and wetclean with an anionic detergent and sizing. Dry in a dryer until 90 percent dry. Finish fabric by using a spray sizing and adequate heat and pressure when finishing.

Restoring color

Local areas. Use carbon paper or a blue pen to cover a small discolored area. To create the white yarn effect use a tapping motion of a white pencil.

Large areas. Use liquid bluing for dying denims. Add four tablespoons or more of liquid bluing (Mrs. Stewart’s) per 1 gallon of water.

Dan Eisen recently retired as chief garment analyst for the Neighborhood Cleaners Association after 33 years with that organization. He is available for seminars, consultations and independent garment analysis. He also has published a book, “The Art of Spotting,” which is an indexed compilation of articles he wrote for National Clothesline and NCA over the past three decades. He can be reached at (772) 340-0909. His address is 274 NW Toscane Trail, Port St. Lucie, FL 34986. His e-mail address is cleandan@adelphia.net.