Saturday, 5 May 2018

Natural Dyeing of Vegetable Fibres

 


I think  of myself as a natural dyer, I do quite a bit of it with ANIMAL fibres. If I want to dye vegetable fibres like cotton or linen I have  use Procion dyes. However, during  a workshop I was running last year I got asked about natural dyeing for vegetable fibres. This was a very apt question as I now live in an area that was, historically, very important in terms of the growth and use of vegetable fibres- namely hemp and flax. I understand that the house I live in was once on land owned by Flaxlands Farm two doors away from my house and that the garden contained a retting pool. 


From this discussion I determined to research natural dyeing of vegetable fibres and try and find, or develop,  a method of dyeing them that gave the same saturated colours and fastness that I can achieve with wool. Many of the naturally dyed fibres and materials that I saw in my research were very pale and to be perfectly honest I am not interested in these. I wanted something that was vibrant, too many people seem to think that natural dyes only give washed out pastel shades. 


So I used my scientific background to take on this challenge. It was essential to consider the chemistry and structure of both the animal and plant fibres. It was here that my ‘old’ textile books came into their own. Different ‘experts’ had their own recipes for scouring and mordanting plant fibres but there was no way of knowing who was just quoting someone else’s method and no explanations of why these methods were noted as being THE way of doing it. For some of the methods I wondered if the author had ever even tried the method before quoting it in print. I have quite an extensive dye section in my textile ‘library’ and used online sources too from open access books, blogs and websites.  


The one thing I do know is that I have not discovered THE way of doing it, but I  currently have a method that works for me, that I can rationalise and partially understand and I think I can improve on still further. 


So I have tried 5 methods of preparing the fibres. I used hemp and cotton from the same sources throughout and each time used the same plant dye liquid extract at the same liquid to dry mass of fibre ratio. I have also dyed wool with the same dye liquid as my standard that I hope to reach with the vegetable fibre dyeing. 


I know that in natural dyeing with wool, the scouring of the fibre  and mordanting are key to the success of the final dyed yarn. I guessed (and found it to be true) that this is also the case with dyeing plant fibres. 


This is the undyed wool and wool dyed with Meadowsweet that I used as comparison 


I will summarise each test and show the results obtained:

For Tests 1-3 Scouring

the fibres were boiled in soft water (I used rain water) for an hour and then

the fibres were then boiled in a solution of soap (20%) and washing soda (6%) for 2 hours


The above seemed to be a standard method given by several authors. I presumed that rain water would be better than tap water. Our water is very hard and keeping tap water away from the soap seemed like a good idea. Using washing soda seemed appropriate to try and soften/ break down the cellulose plant cell walls. 


For test 1: Mordanting

Alum (25%) and  washing soda (6%) were used. I used the timings I often use for mordanting animal fibres of 45 mins to reach boiling point and 45 minutes to boil. 


For test 2: Mordanting 

Tannin (1%) dissolved in hot water and added to water, then fibres added, timing as in test 1


For test 3 Mordanting

This was time consuming as it was Method 1, followed by method 2, followed by method 1 again. 


The actual dyeing: 

Both mordanted (methods 1-3 above)  fibre types -cotton and hemp were then dyed as along with the mordanted wool. 

Meadowsweet  (gathered and dye extracted from the plant material 6 months previously) and used at 200% dye to dry fibre ratio. 


Image of tests 1-3 and Wool for comparison




I was completely underwhelmed with the plant fibres. However, these results did compare favourably with other available photographs of vegetable fibre ‘dyeing’. I was not satisfied. There had to be a better method, after all  for hundreds of years people must have dyed vegetable fibres with natural dyes. 


More research was needed. I decided I would need to try aluminium acetate as the mordant. I also intended to use soda ash instead of washing soda in the scouring. I had read that ash from a plant bonfire would be good and carefully saved this. However when added to the pan for the scouring the pH was barely alkaline so I abandoned that. 


I had read that  three times as much washing soda was needed as soda ash and having considered  the chemical formulae of each this seemed sensible as washing soda crystals contain a substantial amount of water. On taking the pH this was giving a very alkaline solution. (Note I was going to boil this liquid so I would be extremely careful that it did not splash on me, and not get near my eyes or mouth) either before, during or after the scouring. )


Test 4 and 5 : Scouring

The washing soda (105% yes a huge increase) was added to the pan of warm water and dissolved. The fibres were added. The pan was brought to the boil and boiled for 2 hours. The fibres were cooled in the pan. 



Prior to Mordanting for test 4 and 5  the fibres were soaked in boiled tap water for 2 hours before Scouring - this would soften them. 


Test 4 : Mordanting. 

Aluminium acetate (10%) was dissolved in hot water and then added to hot water in the pan. The fibres were added and left overnight. No additional heating was used.

The fibres were stirred at least every half and hour for the first three or so hours. 


This is the result after dyeing with meadowsweet:





This is much more like it. I was pleased with this result. 


Test 5: Mordanting

Tannin (10%)  was dissolved in hot water and the fibres were added and left for 2 hours. Then the fibres were mordanted as in test 4.


This is the result of test 5. I was disappointed as the dyeing is not even, but I do know some natural dyers prefer this look. 




This is an image of all the fibres together


 



What I have learnt: 

To obtain good results in terms of dyeing with natural dyes for animal (protein) fibres is a labour of love. It is time consuming and needs patience and, in my mind, accuracy to get good and repeatable results. For natural dyeing of plant fibres this is even more true, the added time aspect for plant fibres is significant. 

It is possible to dye vegetable  fibres with natural dyes and get even, saturated colours that are fast. My favourite method is Test  4.  However, I still have a couple of tweaks to make to this method before I am happy and of course I need to try it with more than one dyestuff. 

I would welcome comments from others dyeing plant fibres with natural dyes obtained from plants such as I used the meadowsweet here. 




3 comments:

  1. Thank you for this fascinating. I am a bit lazy with my dyeing and don't scour but know I should and will start. I soak vegetable fibres in soy milk, quite diluted to add protein, I think this helps.
    There is a debate at the moment over using soya milk because of the forest being cut down to grow it.

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  2. I've not used soy milk, I need to investigate this. My intuition tells me that it can't be as thorough as the scouring I have investigated but intuition is not scientific! Something to play with during the (hopefully) hot summer....

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