Saturday, July 18, 2009

Natural Dyes -- St. Johns Wort

Joybilee Farm uses natural dyes for their wool, mohair and silk yarns, fibers and fiberart.

Here's the promised update on dyeing with St. Johns Wort flowers.

After boiling the flowers in hard water for 1 hour the bath was strained and left to cool for three days until it started to bubble slightly, and become slightly acidic. The dye bath was a deep red, the colour of raspberry juice.

One 4 oz. unmordanted skein of wool/mohair was put in and allowed to soak at room temperature for 24 hours. The bath was then heated to simmer, 1 tsp. of alum (8% wog) and 1/2 tsp. cream of tartar were predissolved in 1/2 c. H20 and then added to the vat. The skein was simmered for 1 hour and then the pot was removed from the heat and allowed to cool down to room temperature without assistance. The skein emerged from the vat a lovely raspberry colour, which faded somewhat when hanging to dry in the sun.

The second skein was immersed in the vat and the above method followed. It appeared that no colour was laid down on the skein so a tsp of sodium carbonate was added. The skein immediately turned a bright chartreuse. Much of the colour was rinsed but the skein remained a greeny yellow.

A third 4oz. skein was immersed in the vat, brought to a simmer and alum was added. The addition of alum and cream of tartar caused some foaming of the vat and a straw yellow was laid down on the wool.

The vat was pH sensitive, turning red-purple with the addition of acid and green with the addition of alkaline, indication of the presence of anthroquonines in the St. Johns Wort.

Light fastness: The raspberry colour was not as light fast as I would hope for, fading to a brick pink colour when exposed to full sun. But the yellow and chartreuse did not fade as much. I wonder if the raspberry colour would have changed to green with a dip in ammonia?

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