Archive for category: General Dye Information

We have now reached the stage in the course when we start on the adjective dyes, for which a mordant is used. The mordant most commonly used is aluminium sulphate (for animal/protein fibres) or aluminium acetate (for vegetable/cellulose fibres). We also dyed some samples using as a mordant symplocos from the dried leaves of trees of the symplocos species. (Full information can be found here in the blog posts Symplocos leaves as a source of aluminium mordant and More about Symplocos leaves as a mordant.) Symplocos trees are aluminium accumulators and absorb aluminium from the ground in which they grow. This means that the dried leaves are a plant alternative to the manufactured aluminium mordants. Symplocos mordant is currently only available in the US (from Botanical Colors) and Canada (from Maiwa Handprints) although it has also been available in France in the past.

The animal fibres (wool and silk) were mordanted using 10% aluminium sulphate and we used 5% aluminium acetate as the mordant for the vegetable fibres (cotton and linen). We didn’t apply a tannin mordant before the aluminium acetate as, although the tannin step is necessary if using aluminium sulphate on vegetable fibres, aluminium acetate can be used without the tannin step.

The fibres for some dyes were also mordanted with symplocos, so we would be able to compare the results from the two mordanting methods.

For all the tests described below we separated the animal and vegetable fibres, using a separate pot for each fibre category. The reasons for this are as follows: animal fibres tend to absorb dye more readily than vegetable fibres so, if both fibre types are in the same pot, the animal fibres may use up too much of the colour before the vegetable fibres have had a chance to absorb their share of the dye. Also, sometimes, depending on the dye, one fibre type may respond better at lower temperatures and using two pots means the heat level can be adjusted according to the needs of the fibre type.

At the first session we used 100% madder root (Rubia tinctorum), 100% weld (Reseda luteola) and 20% cochineal (Dactylopius coccus) in the form of dried beetles which were not ground into powder. (Incidentally, I never use dyes like madder and cochineal in powder form, unless they are powdered extracts which dissolve in water, as it can be very difficult to remove the tiny particles from the fibres. Also, most dyestuffs can be simmered a second time to extract more colour, but this is more difficult with powders.) All the dyes were put into cotton bags so there would be no need to strain off the dye bath, as the bag of dye could just be removed once the colour had been extracted. (To allow the dyestuff to give more colour to the dye bath, the bag of dye could also be left in the dye pot.)

Note: In workshop conditions, time doesn’t always allow for best practice and dyeing times may have to be shortened. However, it is important not to shorten the dyeing time too much, as this may also reduce the colour fastness. If the dyed colour appears deep enough after 5 to 10 minutes in the dye pot, remove the fibres, pour off most of the dye solution, fill the dye pot up with hot water and then return the dyed fibres. Simmer the fibres in this weakened dye solution for a further 20 to 25 minutes before removing them. For maximum colour fastness the fibres should remain in the dye bath for at least 30 minutes and ideally longer. It is also good practice to allow the fibres to cool in the dye bath and I often leave them to steep overnight. Finally, if the colour was deep enough after only 5 to 10 minutes in the dye bath, make a note to reduce the percentage of dyestuff used in future.

MADDER ROOT

There are several ways of using madder and I am still undecided as to which method gives the best results. In the past I washed the madder first then poured boiling water over it, left it to steep for about a minute, then poured this solution off. I repeated this once more, added the second pour-off to the first and left the solution on one side to make a dye bath later. I then simmered the same madder pieces for about 30 minutes to extract the colour for the dye bath. However, for the experiments described here the madder root was first rinsed well under the cold tap to remove some of the brown and yellow pigments, then it was simmered for about 30 minutes to extract the colour. We also added 2 teaspoons of chalk (calcium carbonate) to brighten the colour. We allowed the dye bath to cool slightly and then the fibres were added and left to steep for about 45 minutes. As madder tends to continue releasing colour over a period of time, we left the bag of madder dyestuff in the pot during dyeing.

In my experience, madder can safely be simmered to extract the colour but it may be advisable to keep the heat below a simmer during dyeing, especially when dyeing wool or silk on an alum mordant. Maintaining this lower temperature seems less important for vegetable fibres and I have sometimes found that even simmering wool and silk fibres can give good reds. I also add a couple of teaspoons of chalk (calcium carbonate) to brighten the colour and I have read that adding cream of tartar to madder dye baths when dyeing silk can make the colour redder and less orange. However, I have not yet tried the latter. Some dyers add bran to the dye bath and although I have done this on occasion, I am not entirely sure why this is done. If bran is added, it must be tied into a bag, as it can be extremely difficult to remove from the fibres. On the whole, much seems to depend on the quality of the madder root and I have generally found that the browner the colour of the root before use, the less red the dyed colour may be. However, having said that, browner madder root can sometimes give equally good reds, so much is probably also luck.

Madder on cotton and linen fabrics

Madder on different types of paper

Madder samples dyed by Jacqui Symons From left to right: no modifier, +acid, +alkali, +copper, +iron

(Photos of full madder samples on four fibres available later)

WELD

The weld was simmered for about 30 minutes to extract the colour. Then the fibres were added and simmered gently for about 30 minutes. The temperature was kept a little below boiling point, as a slightly lower temperature often makes the colours from weld brighter and clearer.

  Left to right: no modifier, +acid, +alkali, +copper, +iron                                                                                                               Fabrics from left: linen, cotton, silk

Close-up of above image

COCHINEAL

The colour was extracted from the cochineal following the multiple extraction method. This means the cochineal was simmered three times and after each simmering the dye liquid was poured off into the dye pot. The three pour-offs formed the dye bath.The fibres were added and simmered for about 30 minutes.

Samples as above for weld (Fabrics from left: linen, cotton, silk)

  Samples as above for weld

Further samples were produced by individual students, some to be shared between all the students.

Ivy (Hedera helix) leaves (top) and ivy berries (below) Dyed by Lizzie Kimbley                                                                        Alum mordant and the usual modifiers in the usual (alphabetical) order

Fustic (Morus tinctoria), alum mordant  Samples (as for weld) Dyed for the group by Claire Bessel

Note: The results from the fustic were more mustard in tone than I had expected and Claire also asked about this, as she had followed the usual methods for dyeing. When I gave her the dyestuff I noticed it looked rather more brown than is usual with fustic and I think this probably influenced the colour. Also, we used 100% dyestuff and a lower percentage might have resulted in more yellow tones.

All photos by Zuzana Krskova

In this session we started sampling adjective dyes, which are dyes that require the use of a mordant, usually alum.

The dyes we used included two of the dyes introduced into Europe at the beginning of the 16th century from South & Central America. They are: Logwood (Haematoxylon campechianum) & Fustic (Chlorophora tinctoria). I had originally planned to use Brazilwood (Caesalpinia echinata), another dye introduced into Europe from South America at the beginning of the 16th century, but this is currently unavailable because it is becoming endangered.

So the third dye we used was Sappanwood (Caesalpinia sappan), from India, Malaysia and South-East Asia. Sappanwood is the form of brazilwood known from the 13th century as a red dye in the East, where it was called “brasil” or “bresil”, meaning “glowing like fire”. It was also known in Europe from the late Middle Ages and was imported by the land route. An indication of its importance can be seen by the fact that it gave its name to the country Brazil. When explorers arrived in that part of South America, similar trees were found growing there abundantly, so the country was named terra de brasil after the tree. It gives colours very similar to those from Caesalpinia echinata, but with a slightly pinker tone.

The mordants we used were 10% aluminium sulphate for the animal fibres and 5% aluminium acetate for the vegetable fibres. We also experimented with symplocos powder as a natural source of aluminium from symplocos leaves and we used this with logwood and sappanwood on both animal and vegetable fibres. (See my earlier post “Symplocos leaves as a source of aluminium mordant”)

Note: for improved colour fastness from logwood on animal fibres, it is advisable to use 24% alum. 

As with the substantive dyes we tested, we applied colour modifiers to the fibres after dyeing.

LOGWOOD 50% (alum mordant) Samples in the following order: Top – linen, silk, cotton Below – No modifier, acidic modifier, alkaline modifier, copper modifier, iron modifier

LOGWOOD 50% (symplocos mordant)  Samples as above for logwood with alum 

I think 50% logwood was too high a percentage for the colour variations from the modifiers to be clearly visible. We should have used no more than 30% to show the effects of the colour modifiers.

SAPPANWOOD 100% (alum mordant) Samples: top – cotton, linen, silk Below –  as for logwood above

SAPPANWOOD 100% (symplocos mordant)  Samples: top – cotton, linen, silk  Below –  as for logwood above

FUSTIC 100% (alum mordant) Samples: top – cotton, silk, linen  Below – as for logwood above 

I was a little disappointed with the fustic results. I had expected much stronger colours and I think we probably didn’t simmer the dyestuff long enough to extract all the colour potential. 

It is always difficult in workshops, when one so frequently seems to be working against the clock, to allow enough time for all the stages and processes involved in natural dyeing. When working at home, it is important to remember that each process needs time and should not be rushed, if one wants the best results. The “look” of the dye bath will often indicate whether more time is needed for colour extraction or colour application and experience is also an important factor.                                                    

At this session we also made our first indigo vat, using washing soda or wood ash water as the source of alkali and sodium hydrosulphite as the reducing agent. We also made a vat using a stock solution.

As an experiment I made a stock solution using wood ash water instead of caustic soda. (See my earlier post “Making and using an indigo stock solution”)

I mixed the indigo powder into a paste with hot water as usual, then added it to about half a litre of wood ash water, which I had first heated to about 50C. I then added sodium hydrosulphite and left the stock solution to reduce. After about an hour, it became a dull yellow-green colour and when I used it to make a vat it worked quite well.

The stock solution made using wood ash water as the source of alkali

INDIGO vat made using one tablespoon of stock solution Upper samples soaked for 2 minutes and the lower samples soaked for 5 minutes Order of fabrics: cotton, silk, linen

All photos above by Ross Belton

On the “Show & Tell” table this session was a display of the little books made by Helen Gibbs and dyed mainly with various tree barks. They are really beautiful and just wonderful to touch and open.

Photos by Helen Gibbs

At the second session of this course we continued washing animal and vegetable fibres and mordanting them with aluminium and tannin. 

We also dyed wool, silk, cotton and linen samples using walnut leaves and walnut hulls (Juglans spp.) After dyeing, the samples were then treated with an acidic modifier (clear vinegar), an alkaline modifier (soda ash), a copper modifier and an iron modifier.

Dyes from walnut leaves and hulls do not require a mordant, so the samples had only been thoroughly washed before dyeing.

1. Samples removed from the walnut leaves dye bath                                                                                                            

2. Samples removed from the walnut hulls dye bath                                                                                                                    

3. Samples waiting to be modified, with the modifier solutions in bottles                                                                            

I usually fill bottles with the modifier solutions in advance, so they are ready to use when needed. It is easy to adjust the quantity added, according to the depth of colour change desired. Start by adding a little modifier solution and then add more if the colour change is too insignificant. Keep the unmodified sample to hand, in order to check that each modifier result gives a slightly different tone and all are a little different from the unmodified samples. With some dyes the differences in shade can be quite dramatic, while with others the differences may be difficult to discern.

4. Results from walnut leaves  

Above: cotton, silk, linen Below from left to right: no modifier, + acid, + alkali, + copper, + iron ( each with wool & silk on the left & cotton & linen on the right) 

(Photos 1, 2, 3, 4 by Ross Belton)

Some notes on dyeing with walnut hulls:

Fresh green walnut hulls, if used before they turn brown, can give lovely rich deep browns but dried walnut hulls usually give paler browns. As we only had dried walnut hulls, we conducted a further experiment with them to attempt to achieve a deeper brown by making the pH of the dye bath more acidic. So after simmering the walnut hulls to extract the colour, we added clear vinegar to about pH4 and then dyed some fibres in the usual way. This produced a deeper brown. 

5. Results from walnut hulls 

(Photo 5 by Zuzana Krskova)

Above: silk, linen, cotton Below as for walnut leaves with extra samples far right showing the results from the dye bath to which vinegar to pH4 had been added. Note that the colour on the wool and silk samples is considerably deeper but the cotton sample shows little difference.

Note: Adding some oak gall solution to the walnut hull dye bath also gives a deeper brown and this is an attractive grey/brown. The oak gall solution can be added to the walnut hull dye bath either in addition to the vinegar or instead of the vinegar. (As a rough guide, add about 250mls oak gall solution per 2 litres of dye solution.) I often use an oak gall exhaust solution in this way.

Although walnut leaves and hulls can be used without a mordant, one of the students added an alum-mordanted wool skein to the walnut leaf dye bath and was delighted to find it dyed a lovely rich yellow colour. Mordanted samples can be added to any substantive dye baths and will often give slightly different colours than those on unmordanted fibres. However, using mordanted fibres does not necessarily mean that the dyed colours will be more light-fast. Indeed, walnut leaves give faster colours without a mordant and using an alum mordant reduces the light fastness. (See Gill Dalby’s book Natural Dyes: Fast or Fugitive for more details.)

In general, dyes from walnuts are more suitable for animal fibres, unless copper or iron modifiers are used. 

At this session we also had a “Show and Tell” table. The photos below show some of the items on the table, all made by the students using the natural dyes we have sampled so far. 

(Photo by Zuzana Krskova)

(Photo by Zuzana Krskova)