Prior to the invention of synthetic dyes, all cloth was coloured using natural matter such as leaves, plant roots, tree barks, insects and lichens. There are many different ingenious processes that our ancestors developed to create vivid light-fast colours, but most of these can be broken down into the following steps:
In this first stage of preparing the cloth for dyeing the cloth is cleaned to remove any oils or fats that are often added to the textile in the spinning and milling of the fibre.
Indigo vat dyeing
Indigo dye cannot be extracted using heat, as the pigment is not soluble in water and so it has to be ‘reduced’ in a fermentation vat which converts it to a soluble form. There are many methods to do this, but I use fruit as my reduction source and regularly feed my vat with fruit sugars. The vat is kept at an optimum temperature of 20 degrees and pH 11 for reduction to take place, resulting in a liquid that looks a bit like greenish urine. The indigo colour only appears when the dye is oxidised, so when the cloth is dipped into the vat it emerges a greenish yellow colour, slowly turning blue as it oxidises. Through multiple dips, the blue pigment on the cloth slowly increases and intensifies.
Most natural dyes will not properly adhere to the cloth fibre unless it has been previously soaked in a ‘mordant’ bath. The ‘mordant’ is most commonly a metal salt, which is absorbed into the fibre and bonds to the dye during the dyeing process. Like most contemporary natural dyers I use an alum mordant which is safe to use and provides beautiful results.
Most of my dyeing follows the simple process of grinding the dried dye material to a fine powder, boiling it to extract the colour, and then heating the cloth in the resulting dye bath. It’s a bit like making tea. The intensity of the resultant colour on cloth is dependant on ratio of dye material to the weight of the cloth submerged in the vat. Few natural dyes such as indigo however cannot be extracted in this way.
Using a resist to create designs on dyed cloth is a practice which has been developed by different cultures around the world throughout history. Broadly, resist dyeing traditions can be described as one of two processes:
Manipulation and pressing of cloth either by tying, stitching, folding, wrapping and clamping
Applying a resist paste to fabric such as mud and plant based pastes
The dye cannot penetrate the fabric in areas where it is masked or under pressure, so when the resist is removed after dyeing the un-dyed areas are revealed.
I love the bold graphics that I can achieve from using clamp resists and these feature heavily in my work.