A large part of the jeans value depends on the quality of indigo denim fabric, is a traditional cowboy color, indigo denim fabric is really with natural or synthetic indigo dyes and dyeing; due to the interests of the trend, many manufacturers also use sulfur dyes, vat dyes and direct dyes dyeing imitation. So how to identify their true and false? Please refer to the following four methods:
1, a drop of concentrated nitric acid solution on sample dyeing and light coating, if indigo dye immediately appears white spots, the edge is green.
2, take the stained sample cut in the glass test tube, placed on the alcohol lamp heating drying. Indigo is hot and red, and it is blue when it cools in a glass tube.
3, the dyeing samples ignited in a flame after leaving the fire immediately, in white porcelain, due to heat sublimation left traces of blue indigo in the white porcelain, and other dyes no such phenomenon.
4, the sample can be treated with two methyl formamide (DMF) solution recycling. If it is true indigo dye, the dye on the sample can be taken by all the apples and is colorless.
The above content is reproduced from MEYIDALE CLOTHING