The technology of blue dyeing
The technology of blue-dyeing comes from the thousand-year-old batik work. First a protective layer is printed on white cotton with a printing block. The blue dye can't colour this protective layer, so the pattern remains undyed there. From the blue dyes that can be found in nature, indigo appeared in the largest quantities. This is why its use spread all over the world.
When the white cotton is ready it is figured by various hand printing blocks (material comes on the row, which we call pap.)
Dyeing by indigo, the figured material is hung on special set, and is dipped into a three metre deep well full of carbon for 15-30 minutes. On removal it is left to oxidise in the air turning the material blue. This process is repeated for 5-10 times, until the desired shade of blue is obtained.
Dyeing by 'Indantren', the material is dyed in a 85°C dye-bath. After the dyeing the (dyed) materials are washed in a sulphuric acid water and the patterns appear in white colour. Then the cloth is dried stretched and dried again.
For more information and patterns see: