IRON (GREEN, GREY & BLACK)

English: Iron
Hindi: Loha
Scientific Name : Ferrum

IRON (GREEN, GREY & BLACK)

Many dyers employ iron as post mordant since it shifts the color and also increases the
fastness property. Sometimes iron solution is used for the preparation of indigo vat as it is a
reducing agent. Most of the natural dyers employ iron solution either made of ferrous
sulphate or they prepare it using rusty iron along with vinegar. Both these iron based
formulation have their own disadvantages viz.when ferrous sulphate is used for the
production of grey or any black shades along with tannin containing plants, the fabric losses
its strength after few days since the residual sulphates present on the fabric reduces the
strength of natural fibers and finally contribute to fabric deterioration on storage. On the
other hand, preparation of iron acetate takes longer time (around 1 to 2 weeks) and if
stored for longer time, the concentration of the solution varies and results in different
shades when employed for dyeing. The pH of the dyed substance needs to be neutralized
properly and thus leads to larger amount of water for use in post washing treatment and
also alkalis. Iron is very strong and reacts with natural raw materials that contain tannin
and produces gray, dark grey to black and should be used with care on protein fibers as it
can make them slightly hard or brittle.