Denim Washing

Dramatic changes have occurred in the function and design of jean garments since the first pairs of jeans were created for gold miners during the California Gold Rush. The evolution of the jeans’ market led to the development of some unique and creative methods for the processing of denim garments. Originally, jeans were marketed and sold as workwear with primary emphasis on their durability and practicality.

But when jeans were discovered and appreciated by consumers as general casual wear, they became fashionable, and new techniques were developed to enhance denim garments and make them more unique. These techniques include garment washing, stone washing, stone washing with chlorine, ice washing, and cellulase enzyme washing. Basically, all of these techniques involve the processing of garments in rotary drum machines.

The first generation of indigo jeans was stiff and uncomfortable when first purchased, due to the finishing techniques used for denim fabrics. Normally after weaving, greige denim is singed, finished with starch and a lubricant, and then mechanically shrunk. This mechanical shrinking did “break” the hand somewhat, but no other processing techniques were employed to provide a soft handle.

Usually, consumers would take a newly purchased pair of jeans home and soften them by washing once or several times before the first wearing. Denim fabric continues to be processed using the same basic finishing system, but after being cut and sewn, denim garments may undergo additional processing.

The second generation of the jeans’ market evolution produced pre-washed jeans by the manufacturer. These jeans had a slightly faded appearance and a softer hand that felt comfortable, as though they had been laundered several times. This trend became fashionable as well, and consumers were willing to pay the extra cost involved in this additional processing. Consumers no longer had to bother “breaking-in” their jeans themselves with the added benefit that the jeans were already shrunk to size with little or no residual shrinkage.

Not long after the introduction of pre-washed jeans, the idea of using abrasive stones to accelerate the ageing process was developed and “stone washing” was born, creating an even more “broken-in” look. Next, chlorine bleach was incorporated in these wash techniques and a whole new paler blue denim family evolved. Then, ice washing was developed, in which the porous stones are soaked in a bleaching agent and then tumbled with dry or slightly damp garments. This process has been given many names, including acid wash, snow wash, whitewash, frosted, etc. Actually, the term “acid wash” is a misnomer since acids alone should never be used for this process.

Most recently, a cellulase wash procedure was developed in which cellulase enzymes were used to accelerate colour and fibre removal. A reduced quantity of stones can be used to create a desirable washed down appearance. This process can be more efficient; since with fewer stones, larger load sizes can be processed, and there is less of an abrasive effect on the inside of the rotary drum.

Famous Denim Terms

• Stonewashing: A process that physically removes colour and adds contrast. Jeans and stones are rotated together for a set period of time. The washing time dictates the final colour of the fabric – the longer the denim and stones are rotated the lighter the colour becomes and more contrast is achieved. The denim is then rinsed, softened and tumble dried.
• River Washing: A washing process using a combination of pumice stones and cellulose enzymes to give denim a vintage, worn hand. The washer is loaded only with stones and fabric for the first cycle. Enzymes are introduced for the second stage in combination with the stones and they are tumbled until a naturally aged look is produced.
• Indigo: The dye used for denim, initially taken from the Indigofera tinctoria plant. The majority of indigo used today is synthetically made. Natural indigo has a slight red cast.
• Tate-Ochi: Japanese term referring to occurrences of ‘Iron-Ochi’ forming in vertical lines in vintage denim. As the thread width is not uniform in vintage denim, the colour fades the most where the thread is the thickest. This creates a white or severely faded thread of several centimetres along a single vertical indigo thread.