Technical Details
The textiles have designs that were applied with a wooden block to the surface of plain-woven cloth. (All the fragments of Gujarati origin are woven from z-spun cotton. The thread count per square centimetre varies, but generally is not lower than 15 x 15, or higher than 25 x 25.) The decoration was applied by using a reserve-dye technique, which means that the design was either defined by a resist application, using wax or a paste, or by only partially preparing the surface with a mordant. In the latter instance, the unprepared areas do not take the dye.
The fabrics can be divided into three groups. The first consists of textiles dyed blue, after the application of a resist which has preserved in parts the original white of the cotton fabric. The process is commonly known by its Malay and Indonesian term, batik, as the technique is highly developed on Java. The source of blue almost certainly was Indigofera tinctoria, the plant commonly used in Asia for a blue dye. The dye agent has been identified as indogotin, but that is found in other plants used for blue dye.
The second group of textiles is dyed with the help of a mordant, a technique that is prerequisite to achieving any shade of red or brown. the mordants used in India were (and are) alum and iron, as well as tannin. Alum, combined with the colouring matter extracted from the dye plant, produces all shades of pink and red. Iron, when used as a mordant in combination with tannin, results in black. Additional organic ingredients can increase the number of shades and hues. The dye itself is extracted from the madder plant Rubia tinctorum. The process of dyeing a cloth red, therefore, requires an initial treatment with a mordant. This can be mixed into a paste and applied to the surface of the fabric, so that the dye will react to it, but will not affect parts that have not been covered. Alternatively, the surface can be treated with a resist, and the mordant and dye then applied by immersion. The former results in a clear outline of design on the surface, but little saturation to the reverse of the fabric, while the latter may show a heavy saturation on the reverse.
Finally, the third group of textiles combines blue with various shades of red, creating a polychrome effect. In general, the blue was the result of an immersion dye bath.