I haven’t found a lot of joy with rhubarb leaf mordant so far… but I do grow rhubarb and often wish I could use the leaves somehow before they reach the compost heap. One chilly day I wondered whether they might just be good in the dyepot–if I heated them surely they would release oxalic acid into the dyebath and even if that is all that happened, raising the acidity level of the bath can be a good thing. Why not?
Then, in with E Scoparia bark. And eventually, two mesh bags full of polwarth fleece. In fact, the last two! I seem to have reached the end of the polwarth fleeces, which seems well nigh miraculous–though they have been just lovely to work with, these are BIG sheep.
The rhubarb leaves did produce a deeper, burgundy shade–than the citrus acidifier in the other pot. Is this a quantity effect, sheer luck…? I am not honestly sure, but I will certainly try it again. The water has to be heated for the dyebath anyway and letting it steep a little before removing rhubarb and adding eucalypt is not too difficult.
In another acid experiment, I have been cleaning out the kitchen cupboards (well, some things over a decade old are leaving the cupboards)–and found this:
Wasn’t I in Brisbane at least 12 years ago the last time I cooked with tamarind?? I put it into a big jar and topped up with water.
Then, into a dyebath with E Nicholii and some of ‘Viola’s’ fleece–she’s a local pet sheep who seems to have some English Leicester parentage. Another gift fleece.
Tamarind on the left, citrus acidifier on the right. Curious! I have another bath with the exhaust dye baths and a second round of leaves steeping (also known as waiting until I have time and inclination…) now.
Way back in December I was thinking about hot and cold mordanting processes. I decided on an experiment inspired by a post by Leena at Riihivilla which led in turn to a blog called From Silk Road. There, Jarek shows experiments with solar mordanting over 28 days, and one of the mordants he is using is Himalayan Rhubarb. Mine is the good old fashioned European eating kind… but perhaps the same principles could be applied? Jenny Dean certainly describes cold mordanting with alum and I have tried that previously with success. I was also curious about the findings of Pia at Colour Cottage. She has undertaken some experiments with rhubarb leaf mordant here and here and found it made no difference to dye uptake or lightfastness. So disappointing!
I started with 1100g rhubarb leaves (and stewed the rhubarb with orange juice to go with waffles… mmmm). Way more rhubarb leaf than necessary for the job, I think. I have no way to know if I am even using the same rhubarb as Pia… but I decided to err on the side of plenty of rhubarb leaf and not committing a huge quantity of yarn. I created two, 25g skeins of Bendigo Woolllen Mills alpaca rich ‘magnolia’, left over from some past workshop I ran. One was subjected to the classic heat treatment in rhubarb leaf solution (45 minutes on a bare simmer), left overnight to cool down and rinsed out.
The other went into a glass jar for a solar treatment, which was quite hot at times. It went into the jar on 16 December and our first 40C day of the year was scheduled for the 18th. I created two more skeins and mordanted them in alum, one using the hot process and the other packed into a bucket with a lid in the sun. Here is the solar mordant rhubarb jar (and some iron soaking in vinegar water on the left), in December. They’re sitting on a concrete surface with a concrete wall behind them. I’m trying for thermal mass in a sunny spot.
Things being what they are (by which I mean I have been too busy to think much about this experiment), I took the yarn out on 13 April 2014. Here it is before removal. There was a little layer of mould stuck to the lid, for those who are wondering. In retrospect, this would have been a great application for Stuff Steep and Store.
Here is the yarn after removal from the rhubarb leaf solution. I’d call that a dye and not only a mordant!
Here is my solar process alum-mordanted yarn after similar neglect for the same period of time.
Finally: my full selection dry and ready for use: no mordant, alum applied with heat, alum applied through solar process, rhubarb leaf applied with heat, rhubarb leaf applied through a solar process.