Discharge printing is a textile printing technique that involves the application of a discharging agent to strip dye from already-dyed cloth in order to produce a printed pattern, which can be either white or colored. It is a method to imprint a design onto dyed fabric. The print pattern is achieved by applying a substance capable of removing the color, such as chlorine or hydrosulfite, to create a white or light pattern on a darker-hued dyed background. A dischargeable dye is employed for dischargeable printing.
Printing is the process of adding localized or patterned color to fabrics. [2] Discharge printing involves dyeing first with dischargeable dyes; subsequently, the dyed fabric undergoes a printing process involving the application of a chemical-infused paste that effectively removes the color imparted by the dye. The process follows steaming and rinsing stages. [3] [4] [5] The selection of reducing agent or stripping agent depends on the dye. [3] "Extract printing" is simply another term for discharge printing. [6] [7]
Vinyl sulfone dyes have emerged as the predominant choice for discharge printing, largely owing to their distinctive chemical composition. Notably, the vinyl sulfone group undergoes breaking of bonds under the influence of reducing agents. [8] [9] In discharge printing, careful dye selection is necessary as certain dyes, like vat dye, resist discharge pastes. [3]
Discharge paste containing reducing agents is used to remove the colour from the dyed ground. Salts of sulfinic acid such as Rongalite may be used as they tend not to weaken the fabric. [4]
Certain enzymes produced by bacteria can break down azo dyes and reduce methyl red to dimethyl p-phenylenediamine and o-aminobenzoic acid. These enzymes might be useful for white discharge printing on azo-dyed fabric. The bacteria responsible for producing these enzymes are identified as Bacillus sp. OY1-2, Xanthomonas sp. NR25-2, and Pseudomonas sp. PR41-1. [10] As of 2007 [update] , enzymes including laccase were under exploration for their applications in discharge printing. [11]
The process of white discharge printing typically entails reducing the dye chemically, resulting in white patterns formed by removing the dyed color. [12] [6]
Fabrics made of denim or other indigo-dyed fabrics undergo a process of discharge using either potassium permanganate or sodium hypochlorite. [13] [14]
When color-discharge printing is used, a dye that can withstand the reducing agent is combined with it. This creates a pattern of color on the fabric that was previously dyed, instead of remaining white. [6] [5]
The polka dot pattern, a pattern of sizable, solidly filled circles that are uniform in size, [15] is a popular pattern with discharge print. [16]
One of William Morris's most renowned textile patterns is 'Strawberry Thief', which stands out for its use of the discharge printing technique. The motif's origin can be traced back to the predation of strawberries by thrushes in the culinary garden of Kelmscott Manor, located in Oxfordshire. Morris utilized the indigo-discharge printing process to create detailed compositions with well-defined outlines. In 1884, he introduced two significant designs: 'Wandle', a remarkable repetition measuring 98.4 x 44.5cm, and 'Cray', which marked the completion of his outstanding contributions to the field of printed textiles. [1] [17]
Calico is a heavy plain-woven textile made from unbleached, and often not fully processed, cotton. It may also contain unseparated husk parts. The fabric is far coarser than muslin, but less coarse and thick than canvas or denim. However, it is still very cheap owing to its unfinished and undyed appearance.
A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and may require a mordant to improve the fastness of the dye on the fiber.
Indigo dye is an organic compound with a distinctive blue color. Indigo is a natural dye extracted from the leaves of some plants of the Indigofera genus, in particular Indigofera tinctoria; dye-bearing Indigofera plants were commonly grown and used throughout the world, in Asia in particular, as an important crop, with the production of indigo dyestuff economically important due to the historical rarity of other blue dyestuffs.
Tie-dye is a term used to describe a number of resist dyeing techniques and the resulting dyed products of these processes. The process of tie-dye typically consists of folding, twisting, pleating, or crumpling fabric or a garment, before binding with string or rubber bands, followed by the application of dye or dyes. The manipulations of the fabric before the application of dye are called resists, as they partially or completely prevent ('resist') the applied dye from coloring the fabric. More sophisticated tie-dye may involve additional steps, including an initial application of dye before the resist, multiple sequential dyeing and resist steps, and the use of other types of resists and discharge.
Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular chemical material. Dye molecules are fixed to the fiber by absorption, diffusion, or bonding with temperature and time being key controlling factors. The bond between dye molecule and fiber may be strong or weak, depending on the dye used. Dyeing and printing are different applications; in printing, color is applied to a localized area with desired patterns. In dyeing, it is applied to the entire textile.
Textile printing is the process of applying color to fabric in definite patterns or designs. In properly printed fabrics the colour is bonded with the fibre, so as to resist washing and friction. Textile printing is related to dyeing but in dyeing properly the whole fabric is uniformly covered with one colour, whereas in printing one or more colours are applied to it in certain parts only, and in sharply defined patterns.
Kasuri (絣) is the Japanese term for fabric that has been woven with fibers dyed specifically to create patterns and images in the fabric, typically referring to fabrics produced within Japan using this technique. It is a form of ikat dyeing, traditionally resulting in patterns characterized by their blurred or brushed appearance.
Resist dyeing (resist-dyeing) is a traditional method of dyeing textiles with patterns. Methods are used to "resist" or prevent the dye from reaching all the cloth, thereby creating a pattern and ground. The most common forms use wax, some type of paste made from starch or mud, or a mechanical resist that manipulates the cloth such as tying or stitching. Another form of resist involves using a chemical agent in a specific type of dye that will repel another type of dye printed over the top. The best-known varieties today include tie-dye, batik, and ikat.
The textile bleaching is one of the steps in the textile manufacturing process. The objective of bleaching is to remove the natural color for the following steps such as dyeing or printing or to achieve full white. All raw textile materials, when they are in natural form, are known as 'greige' material. They have their natural color, odor and impurities that are not suited to clothing materials. Not only the natural impurities will remain in the greige material, but also the add-ons that were made during its cultivation, growth and manufacture in the form of pesticides, fungicides, worm killers, sizes, lubricants, etc. The removal of these natural coloring matters and add-ons during the previous state of manufacturing is called scouring and bleaching.
In textile manufacturing, finishing refers to the processes that convert the woven or knitted cloth into a usable material and more specifically to any process performed after dyeing the yarn or fabric to improve the look, performance, or "hand" (feel) of the finish textile or clothing. The precise meaning depends on context.
Strawberry Thief is one of William Morris's most popular repeating designs for textiles. It takes as its subject the thrushes that Morris found stealing fruit in his kitchen garden of his countryside home, Kelmscott Manor, in Oxfordshire. To print the pattern Morris used the painstaking indigo dye textile printing method he admired above all forms of printing. He first attempted to print by this method in 1875 but it was not until 1881, when he moved into his factory at Merton Abbey, near Wimbledon, that he succeeded. In May 1883 Morris wrote to his daughter, "I was a great deal at Merton last week ... anxiously superintending the first printing of the Strawberry thief, which I think we shall manage this time." Pleased with this success, he registered the design with the Patents Office. This pattern was the first design using the technique in which red and yellow (weld) were added to the basic blue and white ground. Discharge printing was used.
Natural dyes are dyes or colorants derived from plants, invertebrates, or minerals. The majority of natural dyes are vegetable dyes from plant sources—roots, berries, bark, leaves, and wood—and other biological sources such as fungi.
Dyeing is the craft of imparting colors to textiles in loose fiber, yarn, cloth or garment form by treatment with a dye. Archaeologists have found evidence of textile dyeing with natural dyes dating back to the Neolithic period. In China, dyeing with plants, barks and insects has been traced back more than 5,000 years. Natural insect dyes such as Tyrian purple and kermes and plant-based dyes such as woad, indigo and madder were important elements of the economies of Asia and Europe until the discovery of man-made synthetic dyes in the mid-19th century. Synthetic dyes quickly superseded natural dyes for the large-scale commercial textile production enabled by the industrial revolution, but natural dyes remained in use by traditional cultures around the world.
Kalamkari is a type of hand-painted cotton textile produced in the Indian state of Andhra Pradesh. Only natural dyes are used in Kalamkari, which involves twenty-three steps.
Nantong blue calico printing and dyeing has been practiced in most parts of Nantong City, Jiangsu Province, China, since the beginning of Qing dynasty. In modern times, blue calico is used to make daily clothes, mosquito nets, pillowcases, baggage cloth, etc.
Wet Processing Engineering is one of the major streams in Textile Engineering or Textile manufacturing which refers to the engineering of textile chemical processes and associated applied science. The other three streams in textile engineering are yarn engineering, fabric engineering, and apparel engineering. The processes of this stream are involved or carried out in an aqueous stage. Hence, it is called a wet process which usually covers pre-treatment, dyeing, printing, and finishing.
Green textiles are fabrics or fibres produced to replace environmentally harmful textiles and minimise the ecological impact. Green textiles are part of the sustainable fashion and eco-friendly trends, providing alternatives to the otherwise pollution-heavy products of conventional textile industry, which is deemed the most ecologically damaging industry.
Shweshwe is a printed dyed cotton fabric widely used for traditional Southern African clothing. Originally dyed indigo, the fabric is manufactured in a variety of colours and printing designs characterised by intricate geometric patterns. Due to its popularity, shweshwe has been described as the denim, or tartan, of South Africa.
Bagh print is a traditional Indian handicraft originating in Bagh, Dhar district of Madhya Pradesh, India. The process is characterised by hand printed wood block relief prints with naturally sourced pigments and dyes. Bagh print motifs are typically geometric, paisley, or floral compositions design, dyed with vegetable colours of red and black over a white background, and is a popular textile printing product. Its name is derived from the village Bagh located on the banks of the Bagh River.
In textile processing, stripping is a color removal technique employed to partially or eliminate color from dyed textile materials. Textile dyeing industries often face challenges like uneven or flawed dyeing and the appearance of color patches on the fabric's surface during the dyeing process and subsequent textile material processing stages. Stripping is one of the reprocessing methods used to correct undesirable colors and flaws in dyed materials. The efficacy of this process relies on factors such as the dye type, fiber material, and the stripping agents utilized. Additionally, the procedure is recognized by alternative terms, namely back stripping or destructive stripping.