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.
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)
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
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