The topic of my post today is one I have been itching to write since my Indigo workshop, and one I know my students will find beneficial. On the third day of the workshop our indigo vat, which had been behaving perfectly, decided to go sad on us and refused to cooperate. Luckily we were all at a stage where we were getting ready to start packing up from an intensive 3 days, but it was still annoying and perplexing for me as to why it happened all of a sudden...hence the title...Indigo Blues...I was sad that all my tricks would not liven up the vat again.
Around the same time I had an email from one of my past students from last year saying the same thing had happened to her and what could I suggest the problems might be and how could she remedy it. So here goes:
The vat we were using was an organic henna vat, I used powdered Lawsonia inermis (henna) with calcium hydroxide (builders lime) and natural indigo in the 1-2-3 ratio I was taught by Catharine Ellis.
The vat was kept warm at night by standing it in an electric urn filled with water and then covered with plastic and blankets. The air temperature in the day was between 25-30C. In the mornings I would turn the urn back on until the vat got to dyeing temperature, I would stir it, wait at least half an hour and then take the pH and temperature before testing a small piece of white cotton before we started the day's dyeing.
So far so good.
After the vat failed we added the remainder of the 'mother vat' to it in order to spark it back up again but as this did not happen, I realised that if that did not remedy it then I would have to monitor it more closely, as I knew that lack of indigo was not the problem, and the addition of more indigo would not produce darker results, I would just be wasting indigo. I purchased a green garbage bin with a lid from the hardware store that fit my whole vat inside it and carefully transported it back in my van to my studio in Canberra.
I put the vat outside in the sun to warm up, then I took a sample reading from the vat, took its temperature and pH.
|Poor sad looking indigo vat, the flower is small and bubbles are white and pale.|
|The flower is in better shape and shows tinges of blue bubbles|
|Very pale results|
The following day I put the vat outside in the sun again and when the sun moved I bought it inside and heated it in the bain marie and took another sample.
|Slightly better results|
During this time I had been searching in vain to buy Fructose powder which is a more immediate form of sugar/carbohydrate for the vat (as opposed to henna). Fructose is very difficult to find in Australia and especially in Canberra and I had a very frustrating time visiting websites and supermarkets, healthfood stores etc. Henna and fructose both feed the vat to keep the reduction going. Fructose is like a sprinter - it works quickly but burns up fast, whereas henna is like a marathon runner, it takes its time but lasts the distance, and the two substances can both be used as reduction agents in the organic indigo vat.
I then had to go to Sydney for a couple of days to teach a workshop, so the vat was again left to it's own devices. Whilst I was in Sydney, however, I mentioned my fructose dilemma to a friend and fellow-dyer, Sylvia Riley, who owns Silksational, the one-stop shop for fibres, fabrics and dyes.....of course she had fructose powder! What a lifesaver!!
On my return from Sydney I added 40g fructose to my vat, gave it a stir, left it outside in the sun and tested pH iand temperature. The pH was 12, but the dipped colour had gone back to pale again.All my dipped samples were for 2 minutes each in the vat, at least 2 mins oxidising. I another variable I was monitoring, but which is hard to photograph for the blog, was the colour and clarity of the vat below the surface. It should be clear and yellow/green when it is ready to dye with. Mine was murky green and cloudy.
|The bubbles were blue but there was also a blue halo around them.|
|However, the test sample is still very pale.|
Moving house and life got in the way, so the next opportunity to tend to the vat came on 15th Feb, a full 2 weeks after the workshop in Newcastle. I felt guilty for not attending to it every day, but knew if I kept at it it would come good, and that throwing the vat out was not an option because I knew there was indigo in there to use, and I hate wasting materials and money!
I added another 60g fructose to the vat, stirred and rested it. The next day (16th) I came to the studio, stirred it and tested it after half an hour.
My first test at 2.30pm showed a small response from the vat - the colour was much darker than the previous day and so I continued to monitor. At 3pm I added another 50g fructose, stirred and rested the vat then took a sample (#2). I took the pH reading, and to my suprise the pH had dropped to around 8 - far too low for dyeing cotton, but actually predictable given that I had only been feeding the vat with either fructose or henna since it failed a couple of weeks ago. I now needed to re-balance the vat with lime.
|Three tests in one day showing gradual recovery of vat|
|16/2 pH tests at 3.30pm (left) and 4.30pm (right)|
|17/2 The Flower was looking good and the surface started to get that reflective |
'oily' look on the top with a skin starting to form in the afternoon.
|Final test from recovered vat.|
The moral of this story is that your indigo vat may not be completely exhausted even though it is not giving you any colour - it may just need monitoring and the addition of reduction agent (henna, or fructose) and/or lime in order for the vat to recover. If you throw it out you are wasting precious indigo.
Hopefully this post will give you some insights into how your own vat can be monitored and recovered. Obviously if you dye a lot of fabric the indigo WILL eventually run out, however I had kept tabs on this and knew that there was indigo left in the vat...somewhere....!
Here are two examples of resist-paste indigo fabrics I did during the workshop I taught, intentionally alternating paste resist and indigo dipping to achieve the many shades of blue.
|Multiple additions of resist paste and dipping to produce this|
multi-hued indigo cotton fabric
|Resist paste screenprinted onto fine cotton voile.|
Hope this has helped you with your indigo vat problems and happy indigo dyeing for the future!
My website has an events page where I list my upcoming workshops, but please feel free to contact me directly at firstname.lastname@example.org if you would like further information or you would like to book me to teach a specific workshop for your group. You can also comment directly on this post below and I would appreciate your feedback.