Susan Dye, Brian Bond and Ashley Walker copyright 12th October 2020
This experiment was undertaken in 2009 and presented to the London Guild of Weavers, Spinners and Dyers in July 2010. It has not been published until now. It was presernted at:
21 October 2020 in VirBELA
An interdisciplinary conference on natural dyes held in the VirBELA virtual world.
An investigation into dyeing wool with weld. There were four extraction conditions (50°C or 95°C and grown on chalk or clay), four dyebath conditions (70°C vs 90°C and 30 mins vs 90 mins) and twelve mordanting conditions consisting of two time durations, two temperatures and three assistant conditions (no cream of tartar, baking cream of tartar and dyer’s cream of tartar). Half of the samples were left to fade for several months.
The dependent variable was a perceptual ranking of the strength of colour. Samples were also categorised by tonal quality of yellow (straw vs acid).
As expected, time in the dyebath deepened the colour. The source and extraction of the weld did not affect the colour whereas mordanting was very important and interactions were assessed. High alum gave strong, clear, fast colours but it was not the only way to achieve these results. Cream of tartar’s effects were complex. Whether and what type to use depended on several variables.
Dyebaths of 90°C were more likely to produce straw coloured rather than clear acid yellows. However mordanting with 5% alum either without cream of tartar or only using baking cream of tartar also resulted in straw yellows even at low dyebath temperatures.