What is Resist Printing?
Resist printing, also known as reserve printing, involves printing the white fabric first with a paste known as a resist paste. The resist paste prevents the dye from being taken up in a subsequent dyeing process. In resist printing, the fabric is first printed with a resist agent and then dyed. On dyeing, the fabric attains color only on areas where resist agent is not present. After dyeing, the resist agent is removed and the fabric gives the look of a printed pattern.
With the old method of physical resist printing, (hydrophobic) products or printing pastes were applied to the fabric to avoid contact and penetration when the fabric was subsequently immersed in the dyeing liquor (Batik). Now the most diffused printing system is the chemical resist printing carried out with different printing methods, using pastes containing chemicals, which avoid fixation of background dyes (particularly for reactives applied on fabrics made of cellulose fibers).
Resist printing is related to discharge printing in that the end-results are often indistinguishable. The resist style, however, offers the advantage that dyes of great chemical stability, which could not be discharged, can be resisted to give prints of high color fastness standards.
The resisting agents employed, then as now, function either mechanically or chemically or, sometimes, in both ways.
Resist Printing Techniques on Fabric:
There are two types of resist printing techniques on fabric depending upon how the resist is achieved:
1. Mechanical resist, which is achieved by using materials such as resin, clay or wax (African batik prints). These form a physical barrier between the fabric and the dye. They are mainly used for the older, coarser and, perhaps, more decorative styles in which breadth of effect and variety of tone in the resisted areas are of more importance than sharp definition of the pattern.
2. Chemical resist printing, where the fabric is printed with the resist paste followed by over dyeing, either by batch or continuous methods. Chemical-resisting agents include a wide variety of chemical compounds, such as acids, alkalis, various salts, and oxidising and reducing agents. The resist paste prevents fixation or development of the ground color by chemically reacting either with the dye or with the reagents necessary for the fixation of the dye. For example, the use of an acid will prevent the fixation of a reactive dye to a cellulosic substrate. The resist agent is applied prior to dyeing and can be used to achieve a white or colored resist if a dye is incorporated within the resist paste. The dye must not be susceptible to the chemicals used in the resist paste in order to produce an illuminating color.
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Resist print pastes that contain a high proportion of insoluble mechanical-resisting agents impose certain restrictions during the printing process. In copper roller printing, such print pastes are apt to ‘stick-in’ in the engraving, especially in very fine patterns, and to ensure good results a brush furnisher is indispensable in keeping the engraving clean. In screen printing it is important to ensure that the solid particles are not coarse enough to block the screen mesh. It is, therefore, customary in this case to strain the print paste through a sieve which has a finer mesh than that of the actual printing screen.
Some of the resist printing methods are detailed in the following:
- Resist printing on covered background: A pad dye is applied and dried; the printing is carried out with printing pastes containing products avoiding the fixing of background color (but they do not avoid the fixing of any brightener used). The fabric is then dried, steamed and washed (this is the most diffused resist printing method).
- Resist printing by over dyeing: The operations of the resist printing method previously detailed are carried out in inverse sequence; therefore the fabric is first printed and then covered.
- Printing on polyester: Polyester printing must be carried out applying the resist-discharge printing method. Printing pastes containing both the discharge and resist products applied on covered background must be used.
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.