You CAN dye cotton.
More Info: In fact, cotton is one of the easiest fabrics to dye especially if it is not treated. The best dyes to use for cotton fabric are reactive dyes or direct dyes. Reactive dyes work by forming a chemical reaction with the cotton fabric. Reactive dyeing offers good washfastness. With direct dyes, the dye molecules are entrapped within the structure of the fabric. This type of dye will bleed if the dye treatment is not immediately followed by a resin treatment.
The Professional Dyeing Process
Cotton fabric is dyed primarily utilizing two distinct dyeing processes-yarn dyeing or piece dyeing.
Yarn Dyeing-the yarn dyeing process involves dyeing the yarn before it is woven into fabric. This process is necessary when the weave is multicolored such as a gingham check or denim, which weaves blue and white threads together. During this process, yarn is wound on spindles and dye is pushed under pressure from the inside outward and then reversed to fully saturate the threads.
Piece Dyeing-Alternatively, piece dyeing involves dyeing an entire length of fabric at one time. During the piece dyeing process, a dry piece of fabric is immersed in a vat of hot-dye. It is then pulled and pressed between two rollers to extract excess liquid and distribute the dye evenly.
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of Deleware. University of Deleware College of Agriculture and
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“Cotton: From Field to Fabric- Dyeing,
Printing & Finishing.” National Cotton Council of America.
N.p., n.d. Web. 10 Nov. 2011.