Archive for the ‘Dyeing Tips & Recipes’ Category

More experiments with the alkaline extraction method

Tuesday, March 8th, 2016

I am very interested in the dyeing techniques of the past and recently I read Krista Vajanto’s dissertation on Dyes & Dyeing Methods in Late Iron Age Finland, http://urn.fi/URN:ISBN:978-951-51-1790-8, which contains some interesting details about dyes and possible methods for achieving reds (or reddish colours) in areas where madder and madder-related plants were not available. I corresponded with Krista before her dissertation was published and conducted some of my own tests, which I wrote about in my book  A Heritage of Colour. Since then, I have been able to obtain some more information from reading Krista’s dissertation and I have started to experiment further.

One method that would seem to have been used in the Iron Age in northern Europe is what Krista calls “the fermentation of tannins”. Apparently tannin-rich plant materials such as barks and the roots of tormentil (Potentilla erecta) will give red or rust colours if treated in wood ash water or a similar source of alkali. This is very similar to what I call the alkaline extraction method, which I use mainly with madder root and buckthorn bark. In my method, the barks or roots are soaked in wood ash water with no application of heat and the fibres are dyed in this alkaline solution, usually without application of heat or occasionally at a very low temperature. After some time, fermentation will begin and the dye solution will start to become neutral and then acidic.

From my experiments using this method with madder root and buckthorn bark, I have found that if the pH becomes too acidic the red colours become more orange or rust in tone so, in order to obtain true reds, it is important to keep adding alkali to maintain a pH of at least 9. The method Krista used for her experiments with the tannin fermentation method differs somewhat from mine; she fermented the plant materials before adding the fibres, rather than adding the fibres to the wood ash water at the same time as the plant materials. In her dissertation Krista describes how, in her tests, the plant materials were steeped for four weeks in the wood ash water, which started off at about pH10, and then as the time passed the pH values decreased from alkaline to neutral and then to acidic and pH6 as the plant materials fermented.  The fibres were then added to the dye liquid and steeped for two weeks at room temperature. So the main difference between the two methods is that Krista does not add the fibres to the dye solution until it has fermented and become acidic, whereas I add the fibres together with the dyestuff and maintain an alkaline pH while the fibres are steeping in the dye pot and I do not allow the solution to become acidic if I am aiming for reds.

For my latest experiments I decided to first try my method and then the one described by Krista. So I set up some dye baths in glass jars, using alder bark, birch bark, white willow bark and tormentil root. For comparison, I also conducted the same test with buckthorn bark, which I have already used in several tests using the alkaline extraction method. (See my 2013 post Buckthorn Bark)

I half-filled the jars with wood ash water and then added the dye material and wool samples.

AA jars blog postP1030294

The dye liquid became deep red after a day or so and I checked the pH of the solutions every day and added more alkali (wood ash water or soda ash) as necessary to maintain a pH of between 10 and 11.

The samples were finally removed after two weeks. Although they appeared deep red/pink as they were removed from the dye pot, the red colour gradually disappeared as the samples were rinsed and washed, leaving much softer, paler shades. This was interesting, as the colour remains red when using this method with buckthorn bark and does not rinse out.

Below is a photo of the colours achieved. (I would not describe any of the colours as “red”.) There are 2 skeins for each dye; the first skein in each pair is alum mordanted and the second skein is unmordanted.

alkaline extr. method 2016-03-08 11.45.22

From left to right: birch bark, tormentil root, white willow bark, alder bark.

I will now leave the dye solutions to become acidic and ferment before I add a further set of samples to each dye pot.  Once my next tests are completed, I will write a further post on this topic.

For interest, below is a photo of skeins dyed in an alkaline solution of buckthorn bark, following the same method as described in the tests above. The dye bath was kept at around pH10 to pH11 and these skeins are definitely red.

P1030322 blog 5 buckthorn bark

Dyeing with frozen woad leaves

Wednesday, November 13th, 2013

 

Recently I read a post on India Flint’s blog (prophet-of-bloom.blogspot.com), in which India suggested using her method for dyeing with frozen flowers as a way of extracting colour from the leaves of indigo-bearing plants. So I decided to try this method with the last few remaining woad leaves in my dye garden.

 

The leaves must be frozen as soon as they have been collected and they must be completely frozen before they are used, so they should be left in the freezer for as long as this takes. They can also be left in the freezer for a longer period, if you don’t want to use them immediately.

 

I managed to collect just about enough leaves for a small trial dye bath and as soon as I had harvested them, I put them into a sealed plastic bag and left them in the freezer for about 24 hours. I then removed the leaves from the freezer and squeezed the bag to crush them before removing them from the bag. I then immersed the leaves in a bowl of lukewarm water. Out of interest I checked the pH of the dye liquid and it was pH7 (neutral). I added some silk and wool fibres, squeezed them with the leaves for a few minutes and then left them to soak for about half an hour. After this time the fibres looked blue. I then left the samples to soak for several more hours, after which they had become a grey/blue. I removed this first set of fibres and added soda ash to the dye bath to make it alkaline (about pH9).  I added a wool skein to this alkaline liquid and left it to soak for several hours. This sample became tan/pink.

 

The results can be seen in the photos below. (Note: The actual blue colours are rather greyer in tone than they appear in the photo.) The blue/grey colours are shades that are sometimes obtained from an almost exhausted woad vat and are also similar to those I often achieve from frozen purple flowers, such as pansies, using the same freezing and dyeing method. However, I was able to harvest only a few leaves for this experiment, so I intend to try it again next year earlier in the growing season and see whether a higher percentage of younger leaves gives different results. I will also try removing the fibres as soon as they have become a reasonable blue, rather than leaving them in the dye bath for a longer period, as it seems possible that prolonged soaking caused the blue colour to become greyer in tone.

The pink/tan colour is similar to the shades obtained from woad leaves if they are simmered to make a dye bath.

 

Although this method may not necessarily produce true indigo blues, it is certainly a useful way of using woad leaves and I am grateful to India for suggesting it. However, without experimenting further and conducting fastness tests, I cannot be sure that the colours achieved from woad leaves by this method would be as fast as those achieved by the more conventional methods.

 

 

281 frozen woad leaves

 

 

 

 

Buckthorn Bark

Monday, September 2nd, 2013

 

Buckthorn bark (Rhamnus spp.) is an extremely useful dye which can be used very successfully without a mordant and gives colours ranging from mustard yellows to true madder-type reds.  (The bark of alder buckthorn (Frangula alnus) can be used in the same way as buckthorn bark and gives similar colours.)

 

For reds, buckthorn bark is best processed using the alkaline extraction method, which means soaking the bark in a solution of water and an alkali, such as washing soda or wood ash water. The exact proportions of water to alkali don’t really matter as long as the solution has a pH reading of 10 to 11. As the solution begins to ferment it will become more acidic, so more alkali may need to be added to maintain the degree of alkalinity necessary for reds and pinks. If fibres are added at different stages, a range of shades can be obtained, with colours becoming more orange and less pink in tone as the alkalinity decreases. No heat should be applied to solutions with high alkalinity and the colours develop gradually on the fibres in a cool solution.

 

The fibres can be added together with the buckthorn bark and left to soak with the dyestuff until a suitable depth of colour has been reached. Alternatively, the dye solution can be poured off once the colour has developed and the fibres can be added to this dye solution. Whichever method is selected, no heat should be applied.

 

for blog 172 buckthorn bark alkaline extraction samples p113 lower

 

This photo shows some of the colours achieved from buckthorn bark using the alkaline extraction method described above. (No mordant)

 

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This photo shows some colours from the exhaust dye bath. (No mordant)

 

The alkaline extraction method is a very useful way of extracting and applying colour and can be used with a variety of dyes. It is one of the techniques I shall be featuring in my new book “A Heritage of Colour”, which is currently scheduled for publication in February 2014 and which will include details for using over 50 plants, including buckthorn. I will give more details about this new book in a later post.

Indigo dyeing with vinegar

Tuesday, December 11th, 2012

 

I have been intending for some time to try the vinegar method of dyeing with fresh leaves from indigo-bearing plants and this year I managed to collect enough Japanese Indigo (Persicaria tinctoria) leaves to make an experimental vat.

 

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These rather pathetic-looking plants did eventually  grow sufficiently well to provide some leaves for a small test vat but still only produced enough to fill about a quarter of a small bucket.

 

I must admit that I have been a little sceptical about the likelihood of being able to produce fast blues  from indigo-bearing leaves using only water and vinegar and no heat.  But obviously one should always try a recipe before offering an opinion.

For this method, the leaves must be processed as soon as they have been picked and, after washing them, it is important to cut or shred the leaves very finely. (First of all, I made the mistake of using a stainless steel demiluna chopper on a wooden chopping board and as a result I wasted some of the dye potential and now have a chopping board permanently stained blue. I considered using a liquidiser but decided in the end to cut up the leaves with scissors.) Then I poured enough cold water over the leaves to cover them and added a little clear vinegar to the water – about 15mls per litre – then vigorously kneaded the leaves in the water-vinegar solution for several minutes until the liquid became bright green. I strained off this liquid into a dye pot and then made a second water-vinegar solution and repeated the process with the same leaves. I then squeezed the leaves very well before straining off this liquid and adding it to the bright green liquid in the dye pot. Then I added the wetted-out fibres and left them to soak in the liquid for about one hour until they had become blue in colour. Then I rinsed the fibres and hung them up to dry. The photo below shows the dyed wool and silk.

 

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I decided to try this method with woad leaves (Isatis tinctoria) but unfortunately, as I had already harvested virtually all my woad leaves a few weeks before, all I managed to find for this experiment were about ten thin leaves left clinging to the plants.  So I wasn’t really expecting this test to be successful but these few leaves dyed the fibres a similar, but somewhat paler, blue. I would hope to get deeper blues from a larger quantity of woad leaves but sadly that will have to wait until next year.

Only time and several washes will prove whether this method gives blues which are light- and wash-fast, so I shall reserve my judgement until a later date. Certainly, if fast blues can be produced so easily and quickly, one wonders why dyers would bother with the more usual way of using fresh woad and Japanese Indigo leaves. And I suppose that thought is what made me sceptical about the merits of this method in the first place.

Walnut hulls & madder root again – but no purples or pinks

Thursday, April 5th, 2012

I have now done some more experiments using a combination of walnut hulls and madder root – this time using dried madder root, rather than madder extract. As the photo below shows, sadly no purple or pinks were achieved. So I assume that there must be something in the madder extract that caused the results I described in my last post. Whatever this “something” may be, it would not seem to be present in dried madder root.

From left to right: alum mordant, no mordant, no mordant + alkali, no mordant + iron, no mordant + (1) iron & (2) alkali

I simmered the walnut hulls and madder root together for about 30 minutes, then strained off the dye liquid and added the first two samples. After these had been dyed, I added the three remaining samples. After these had simmered for 45 minutes, I removed them and divided the dye bath into two. I added washing soda to one dye bath and iron to the other. I modified one dyed sample in washing soda and two in iron. I then removed one sample from the iron-modified dye bath, rinsed it well then added it to the dye bath containing the washing soda.

Sadly, no purples or pinks were achieved but the reddish-browns are attractive shades.

Not what I was expecting

Tuesday, March 20th, 2012

I tend to stick to a somewhat limited palette when producing items for myself, so I am trying to extend the range of colours I usually work with. My preference seems to be for the strong reds, purples, pinks and blues that come from madder, woad, indigo, cochineal and logwood. So for a change I decided to aim for a rich medium brown that I hoped would provide a pleasing contrast with some indigo-dyed wool I had earmarked for a jacket.

Walnut hulls seemed a reasonable choice of dye and I knew I had a container full of sludge from the fresh green walnut hulls I had collected and processed last year. Fresh green walnut hulls usually give much richer browns than dried hulls and when I used this sludge last year I achieved lovely warm shades, so I was full of enthusiasm. I used unmordanted handspun wool and set up the dyebath. First, I simmered the sludge in its accompanying liquid (plus extra cold water) for about 45 minutes to extract more colour. Then I strained off the dye solution and added more cold water, plus some oak bark solution to increase the tannin content, as this can improve the depth of colour from walnut hulls. The wetted skeins were then put into the dyebath and gently simmered for about an hour, before being left to steep as the solution cooled down.

However, when I inspected the colour on the skeins it became clear that I wasn’t going to achieve the depth of colour I wanted – instead a mid greyish brown (typical of the shades from dried walnut hulls) seemed to be the result. I was still determined to aim for a rich warm brown, so I decided to add some madder extract to the walnut solution, in the hope that adding some red would produce the colour I wanted. I mixed about a teaspoon of madder extract to a paste with hot water, removed the skeins from the dyebath and stirred the madder paste into the dyebath, then returned the skeins to the pot.

To my surprise, the (unmordanted) skeins almost immediately became a purple colour, not the rich brown I was expecting. Then I remembered this had happened before several years ago and I had assumed at that time that it was just one of those strange results that would never be repeated.

I had also made a dyebath from oak leaves and oak bark, as I wanted two slightly different shades of brown, and I had added madder extract to this dyebath too. This time the skein became a rich pink/purple. Both the purple and pink skeins retained their colours after they had been washed and rinsed.

So how do I account for these unexpected results? Well, leaving aside the possibility that some mysterious colour spirit had decided I am destined to work always with the same colour palette, I can only assume that the tannin in the walnut hulls and oak leaves and bark reacted with some pigments or chemicals in the madder extract to produce these purple colours. Perhaps the madder extract contains elements from the processing that are not present in madder root, so now I need to try out this combination using madder root, rather than extract. If this does not produce these purple colours, then the assumption would probably be that something present in madder extract , but not in madder root, was the cause of the purple colours.

If anyone has any other ideas as to how and why these purple colours resulted from these dye combinations, please let me know!

What I was expecting:

What I achieved:

P.S. to the indigo/lime/fructose vat

Wednesday, February 29th, 2012

I have now experimented with a stronger vat, this time using 2 teaspoons indigo, 4 teaspoons calcium hydroxide and 6 teaspoons fructose – that is, double the quantities used in my first vat.

I dyed the same quantities of fibres following the same methods but the depth of blue I achieved was no deeper than from the first, weaker, vat. This would indicate that this vat gives pale to mid blues but not the deep blues which other indigo dyeing methods give. I wonder whether this vat may be best used for patterning fabrics employing resist techniques, rather than for dyeing skeins of fibre as I tend mainly to do. I also noticed that this vat left the wool feeling rather harsh. However, I didn’t use a vinegar after-bath, which might have been advisable to counteract the effects of the strong alkalinity of this vat. (I never usually use a vinegar after-bath, so I’m afraid it didn’t occur to me to do so after this vat.)

If anyone else has any comments to add on using this type of indigo vat, I’d be delighted to receive them.

1-2-3 Indigo Fructose/Lime vat

Sunday, February 19th, 2012

I have read several times about Michel Garcia’s indigo vats – in reports from the ISEND natural dye conference in France, in posts on Helen Melvin’s blog and most recently in an article by Jane Deane in The Journal for Weavers, Spinners and Dyers. Michel Garcia is a bio-chemist who has been researching indigo dyeing for many years and he has developed indigo vats that are simple to make and ready to use in a short space of time. Michel wants his environmentally-friendly methods to reach as many dyers as possible, so I decided to try out one of his recipes and then pass on the information, so others can use it too.

The vat I have tried is his 1-2-3 vat, so called because of the proportions of the ingredients used: 1 part indigo, 2 parts slaked lime (calcium hydroxide) and 3 parts fructose. This means that for 10gm indigo you would need 20gm calcium hydroxide and 30gm fructose, for 20gm indigo you would need 40gm calcium hydroxide and 60gm fructose and so on. Calcium hydroxide or slaked lime should be available from builders’ merchants but I bought mine on the internet from Amazon. I purchased fructose from our local health food shop but it may also be available in some supermarkets. For my  trial vat I used 1 teaspoon indigo powder, 2 teaspoons calcium hydroxide and 3 teaspoons fructose.

NB Calcium hydroxide should be handled with caution. It can irritate skin and lungs and cause serious injury if it comes into contact with the eyes. Do not pour water onto it but add it slowly to water.

To make the vat, start by putting hot water (around 40C to 50C but no hotter) in a dye pot or heatproof strong glass jar. Mix the indigo powder with hot water to make a smooth paste and make sure no gritty particles remain unmixed. (Jane Deane’s article gave a useful tip for mixing this indigo paste: put the powder and water in a small container with a well-fitting lid and add some marbles (or marble-sized smooth stones). Then shake vigorously to incorporate all the indigo particles in the solution. I’ve tried this and the marbles really help to make a smooth paste.)

Add this indigo solution to the hot water in the vat or jar, then stir in the calcium hydroxide. Finally add the fructose and stir well. The vat may take up to 45 minutes to be ready but mine was ready to use in about 5 minutes. The vat can then be used in the same way as other indigo vats. One recommendation was to add the fibres dry, rather than wetting them first, but I forgot this and wetted out my wool skein automatically, as I usually do, and it didn’t appear to matter. I suspect this recommendation probably refers mainly to cotton and silk fabrics, which I often add dry to indigo vats anyway. Another suggestion was that the pH of this vat might be too high for wool. However, my vat was pH11 but I dyed wool in it without any obvious ill effects. The wool remained in the vat for about 30 minutes and dyed to a mid-blue; further dips didn’t increase the depth of blue. I also added some silk fabric and a cotton skein to the vat and both dyed to a similar shade of blue as the wool. Jane Deane’s article implies that this vat is likely to produce only pale to mid blues but the lack of a deep blue from my vat may have been because I only used 1 teaspoon of indigo to make this trial vat. Anyway, I shall experiment further with this method and see whether deep blues can be achieved.

I found this method of indigo dyeing extremely simple and effective and, if it also dyes deep blues, it could be very useful.

This shows the vat with the ingredients added

This shows the vat ready to use

This shows the wool skein in the vat

This shows the skein on removal from the vat

This shows the dyed wool skein

Dyeing with Hedge Bedstraw

Wednesday, February 1st, 2012

I have been keen to experiment again with the native bedstraws but, since we moved house and I left my precious dye garden behind, I have been finding it difficult to harvest suitable bedstraw roots. The roots of the Lady’s Bedstraw (Galium verum) plants that I have planted in my new garden are too immature and it is against the law to uproot plants in the wild, so it seemed that any experiments might have to wait a year or two for my own plants to be ready to harvest.

However, thanks to the generosity of Leena Riihela in Finland (www.riihivilla.com) who kindly sent me some roots from her own garden, I have been able to experiment with Hedge Bedstraw, (Galium mollugo).

Compared with the roots of madder (Rubia tinctorum), bedstraw roots are very fine and delicate, and these bedstraw roots were very precious as they had come from such a long way away. So I wanted to make sure that I didn’t waste them.

For these tests I used mainly alum-mordanted wool, except for some unmordanted samples from the exhaust dyebaths. To prepare the dyebaths, I first soaked the roots overnight in water, then poured off this liquid. I then steeped the roots twice in boiling water for about 1 minute each time and added this liquid to the soaking water to make the first dyebath. I then simmered the roots twice more, using each simmering liquid for a separate dyebath. In the photos below, the orange colours on the left were from the soaking water plus the two steeping waters and also from the first 2 simmerings. I then simmered the roots again twice for about 45 minutes and used this liquid for another 2 dyebaths. The middle range of shades on the photos were from these 3rd and 4th simmerings, the redder one with an alkaline modifier (washing soda). The range on the right came from exhaust dye baths, with some unmordanted and some alum-mordanted samples. Once the fibres had been added to the dyebath, I didn’t worry too much about the temperature and allowed the dyebaths to simmer gently to improve colour take-up. (This simmering is not something I would do when dyeing with madder – see below)

I decided to work in this way, rather than combining all the extractions, because my belief is that the richest true reds lie under the yellows and browns and the best way to get reds is to first use up these yellows and browns. I don’t know whether this belief is correct but my experiences suggest it seems a good way to get reds rather than oranges. 

I now use this method when dyeing with madder and it seems to work well. After washing the madder roots well, I simmer them to extract the colour for the first dyebath, remove the roots to use again for a second dyebath and then reduce the temperature before adding the fibres.  Once the fibres have been added, I don’t simmer the madder dyebath and I keep the temperature hot but not too hot – i.e. well below simmering point. The roots can then be simmered again to extract more colour for a second dyebath. Indeed, madder is a most generous dye and the roots can often be simmered several times before the dye is exhausted, giving colour for yet more dyebaths.

I think that, when I next dye with the bedstraws, I will probably keep things simpler and try something closer to the method I use with madder. So, after soaking the roots overnight,  I will simmer them once for about 30 minutes and use this solution for my first dyebath. I will then simmer the roots again (probably for about 45 minutes) for a second dyebath and to make sure no precious dye is wasted, I will simmer the roots at least once more for a further dyebath. But first I must wait for my bedstraw roots to be mature enough to harvest.

A range of shades from Hedge Bedstraw (Galium mollugo)

A close-up image of some of  the Hedge Bedstraw colours.

Making and Using an Indigo Stock Solution

Sunday, November 6th, 2011

Thanks to Helen Melvin’s booklet on indigo dyeing, “The Colour of Sea and Sky”, and Helen’s comments on the merits of making an indigo stock solution, I decided to experiment again with this method of making an indigo vat. This was the method I first used with indigo over 30 years ago and Helen’s book reminded me of the advantages of the stock solution method, among them the fact that indigo reduces more efficiently in a concentrated alkaline solution and there is therefore less likelihood of wasted, undissolved indigo. Also, using a stock solution means that the colour can be built up relatively easily.

So why did I stop using the stock solution method? The main reason is that the one-step-bath method I generally use now, and which appears in my books, is more practical for one-day workshops, as the vat is quick to make and this enables me to demonstrate how to make and use an indigo vat in a short space of time. However, after we have used this vat there is often some indigo remaining, which gets thrown away, (unless students can take some solution home with them). Indeed, I often tell students that this vat is even better on the second day, as the indigo has had more time to reduce completely. The other reason for abandoning the stock solution method is my desire to avoid the use of caustic soda, which can cause bad burns if not used with great care.

Helen’s stock solution recipe is quite simple and involves mixing 50gms of indigo powder with 2 tablespoons each of caustic soda (the alkali) and thiourea dioxide (the reducing agent).

For my stock solution I used sodium hydrosulphite (hydros) as the reducing agent and this also works perfectly. I first mixed the indigo powder to a smooth paste in 4 tablespoons of very hot water in a large heatproof jar. I then topped this up with hot water but no hotter than 50C, which is about as hot as a hand can tolerate. (NOTE: Don’t fill the jar too full and leave enough space for any bubbling or fizzing that may occur.) Then I very gently stirred two tablespoons of caustic soda into this solution, followed by two tablespoons of sodium hydrosulphite (or use thiourea dioxide instead of hydros). This is the stock solution. NB Remember to wear rubber gloves and bear in mind that both caustic soda and the reducing agent should be added carefully to water and never pour water directly onto them.

Keep the jar warm and after about 45 minutes the stock solution mixture will become a clear amber colour, although the surface, which is in contact with oxygen from the air, will be a dark blue colour with a lustrous sheen. The stock solution is now ready to use.

To make the vat, fill the container up with water no hotter than 50C, add a teaspoon of hydros (or alternative reducing agent) and a teaspoon of washing soda and allow to stand for a few minutes. Then gently stir in one or more tablespoons of stock solution, according to the size of the vat and the depth of blue required. The vat can then be used as usual and more indigo stock solution can be added as necessary.

Further information on making and using a stock solution and many more recipes can be found in Helen’s booklet “The Colour of Sea and Sky”, which I highly recommend. And of course, like all Helen’s books, it has a lovely hand-painted cover.

The photo below shows a range of blues from indigo