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Tie-dye is a modern term invented in the mid-1960s in the United States for a set of ancient resist-dyeing techniques, and for the products of these processes. The process of tie-dye typically consists of folding, twisting, pleating, or crumpling fabric or a garment and binding with string or rubber bands, followed by application of dye(s). The manipulations of the fabric prior to application of dye are called resists, as they partially or completely prevent the applied dye from coloring the fabric. More sophisticated tie-dyes involve additional steps, including an initial application of dye prior to the resist, multiple sequential dye and resist steps, and the use of other types of resists (stitching, stencils) and discharge. Unlike regular resist-dyeing techniques, tie-dye is characterized by the use of bright, saturated primary colors and bold patterns. These patterns, including the spiral, mandala, and peace sign, and the use of multiple bold colors, have become cliched since the peak popularity of tie-dye in the 1960s and 1970s. The vast majority of currently produced tie-dyes use these designs, and many are mass-produced for wholesale distribution. However, a new interest in more 'sophisticated' tie-dye is emerging in the fashion industry, characterized by simple motifs, monochromatic color schemes, and a focus on fashionable garments and fabrics other than cotton. A few artists continue to pursue tie-dye as an art form rather than a commodity. ==Dyes, fabrics, and discharge agents== A variety of dyes can be used in tie-dyeing, including household, fiber reactive, acid, and vat dyes. Most early (1960s) tie-dyes were made with retail household dyes, particularly those made by Rit. In order to be effective on different fibers, these dyes are composed of several different dyes, and thus are less effective, and more likely to bleed and fade, than pure dyes designed for specific fibers. This is the basis for the famous 'pink socks' phenomenon that occurs when fabrics dyed with mixed dyes are washed with other garments. Most tie-dyes are now dyed with Procion MX fiber reactive dyes, a class of dyes effective on cellulose fibers such as cotton, hemp, rayon, and linen. This class of dyes reacts with fibers at basic (high) pH, forming a wash-fast, permanent bond. Soda ash (sodium carbonate) is the most common agent used to raise the pH and initiate the reaction, and is either added directly to the dye, or in a solution of water in which garments are soaked before dyeing. Procion dyes are relatively safe and simple to use, and are the same dyes used commercially to color cellulosic fabrics. Protein-based fibers such as silk, wool, and feathers, as well as the synthetic polyamide fiber, nylon, can be dyed with acid dyes. As may be expected from the name, acid dyes are effective at acidic (low) pH, where they form ionic bonds with the fiber. Acid dyes are also relatively safe (some are used as food dyes) and simple to use. Vat dyes, including indigo, are a third class of dyes that are effective on cellulosic fibers and silk. Vat dyes are insoluble in water in their unreduced form, and the vat dye must be chemically reduced before they can be used to color fabric. This is accomplished by heating the dye in a strongly basic solution of sodium hydroxide (lye) or sodium carbonate (caustic potash) containing a reducing agent such as sodium hydrosulfite or thiourea dioxide. The fabric is immersed in the dye bath, and after removal the vat dye oxidizes to its insoluble form, binding with high wash-fastness to the fiber. However, vat dyes, and especially indigo, must be treated after dyeing by 'soaping' to prevent the dye from rubbing (crocking) off. Vat dyes can be used to simultaneously dye the fabric and to remove underlying fiber-reactive dye (i.e., can dye a black cotton fabric yellow) because of the bleaching action of the reducing bath (see below). The extra complexity and safety issues (particularly when using strong bases such as lye) restrict use of vat dyes in tie-dye to experts. Discharge agents are used to bleach color from previously-dyed fabrics, and can be used in a sort of reverse tie-dye. Household bleach (sodium hypochlorite) can be used to discharge fiber reactive dyes on bleach-resistant fibers such as cotton or hemp (but not on wool or silk), though the results are variable, as some fiber reactive dyes are more resistant to bleach than others. It is important to bleach only as long as required to obtain the desired shade, and to neutralize the bleach with agents such as sodium bisulfite, to prevent damage to the fibers. Thiourea dioxide is another commonly used discharge agent that can be used on cotton, wool, or silk. A thiourea dioxide discharge bath is made with hot water is made mildly basic with sodium carbonate. The results of thiourea dioxide discharge differ significantly from bleach discharge. Discharge techniques, particularly using household bleach, are a readily accessible way to tie-dye without use of often messy and relatively expensive dyes. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tie-dye」の詳細全文を読む スポンサード リンク
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