Textile printing is the process of applying colour 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.
In printing, wooden blocks, stencils, engraved plates, rollers, or silkscreens can be used to place colours on the fabric. Colourants used in printing contain dyes thickened to prevent the colour from spreading by capillary attraction beyond the limits of the pattern or design.
Traditional textile printing techniques may be broadly categorised into four styles:
- · Direct printing, in which colorants containing dyes, thickeners, and the mordants or substances necessary for fixing the colour on the cloth are printed in the desired pattern.
- · The printing of a mordant in the desired pattern prior to dyeing cloth; the color adheres only where the mordant was printed.
- · Resist dyeing, in which a wax or other substance is printed onto fabric which is subsequently dyed. The waxed areas do not accept the dye, leaving uncoloured patterns against a coloured ground.
- · Discharge printing, in which a bleaching agent is printed onto previously dyed fabrics to remove some or all of the colour.
- · Resist and discharge techniques were particularly fashionable in the 19th century, as were combination techniques in which indigo resist was used to create blue backgrounds prior to block-printing of other colours.
Modern industrial printing mainly uses direct printing techniques.
The printing process does involve several stages in order to prepare the fabric and printing paste, and to fix the impression permanently on the fabric:
- · pre-treatment of fabric,
- · preparation of colors,
- · preparation of printing paste,
- · impression of paste on fabric using printing methods,
- · drying of fabric,
- · fixing the printing with steam or hot air (for pigments),
- · after process treatments.