Andrea Hennessey’s Special Rug made from Hand-dyed Wool Yarn

Customer Andrea Hennessey has kindly sent us some photographs of a rug she was commissioned to make for a recently renovated chapel in France. Using the bespoke stained glass windows as her inspiration she set about hand-dyeing her wool yarn to match the colours as closely as possible.


Andrea uses Fibrecrafts acid dyes for her wool yarns and here are her useful notes about the process she uses.

“I really like and trust these dyes for their light- and colour-fastness, and I find them cost-effective. I can achieve all the colours and tonal variations I need by mixing just the primaries in varying proportions and strengths (‘depth of shade’ or ‘DOS’), but I do use different values of each. For example, for a warm yellow I use Golden Yellow; for a cool, bright yellow I use Lemon Yellow – mixed with a blue, each of these yellows will give a wide range of very different greens.”

“No result is ever ‘wrong’ – I save every formula, write it on a tag label, and tie the label to a 10g test skein which I keep for future reference. If the result isn’t quite what I’m after, that’s OK – it’ll be the perfect colour for another project in the future. Over time, I’ve built up a fair selection of tonal values in every hue.”


“I use a 20L boiler for batch dyeing multiple skeins. The rug is 2.70m long x 1.8m wide and needed 11Kg of wool – my boiler was indispensable! My particular model comes with a manually controlled thermostat, which gives me control over how slowly I bring the dye bath up to temperature (83°C – 95°C) after immersing the wool. It’s very important to raise the temperature slowly to avoid felting the fibres. (A long thermometer really comes in handy.)”

“I usually add sodium sulphate (Glauber’s Salt) to the dye bath first, before adding the dye. This forms a weak bond with the wool and keeps the dye molecules moving around, looking for their own receptor sites on the wool. Eventually the dye molecules gain the upper hand, but in the meantime the dye is more distributed, giving a more even result. I’ll omit the Glauber’s Salt and use a lesser ratio of water to Weight of Fibre (WOF), if I want a less even, or mottled, effect.”

Thank you Andrea for allowing us to share this valuable account.