Archive for the ‘Dyeing Tips & Recipes’ Category

Alum Mordants

Saturday, December 13th, 2008

Readers of my latest book “Colours from Nature” (details on this blog under “Publications”) will probably notice that my recipe for mordanting animal fibres with alum has changed slightly. I now use 10% alum & no cream of tartar, instead of 8% alum + 7% cream of tartar. The reasons for this are as follows: cream of tartar, potassium hydrogen tartrate not the culinary sodium pyrophosphate, was difficult to obtain here for a while, so I got used to mordanting without it. After some experiments, I found that alum used alone at 10% (i.e. 10gms alum per 100gms fibre) seemed the lowest % of alum that gave good results, so I adopted this as my method of mordanting animal fibres. When I started using cream of tartar again, I found that for some reason it wouldn’t dissolve properly & remained as a sludge at the bottom of the pan. So I decided it was simpler (& less wasteful) to use alum alone. 10% alum works well & is very convenient if you make it into a solution as I explain in the book. With a solution of 100g alum dissolved in 1 litre of boiling water, when you use 10% alum, you use the same quantity of alum solution in mls as weight of yarn in gms. E.g. To mordant 450gms wool you need 450mls alum solution. This seems so much simpler & the results are just as good, in my experience. In fact, with some dyes, such as madder, I think the results are better. And the alum solution can be stored indefinitely in a glass or strong plastic container with a well-fitting lid. Also. it seems much easier to measure out a liquid than a powder. But of course, if you have your own preferred recipe for alum mordanting, then that’s the best method for you.

Recently it has become possible to obtain aluminium acetate in the UK & this has made mordanting vegetable fibres, & also silk, so much easier. 5% alum acetate used in a single process can replace the more time-consuming tannin & alum mordanting processes commonly used for vegetable fibres. Aluminium acetate is widely used in Japan as a mordant for silk & I have found it to be excellent for both silk & vegetable fibres.

PS  One last comment: Before I throw away the used 10% alum mordanting bath, I usually add one final skein to it & mordant it as usual. I label it “alum exhaust”, just in case there wasn’t enough alum left to have even a tiny mordanting effect, & then use it with a dye, such as madder, which will fix both with & without a mordant.

A Postscript to Rhubarb

Friday, December 12th, 2008

With the exception of the pale pink skein (dyed in cochineal on an alum mordant) & the pale blue skein (dyed in indigo), this photo shows some colours achieved from various dyes, using rhubarb leaves as a base or alternative mordant. The reddish colours are from madder, the pinker shades are from cochineal, the brown & tan colours are from cutch & the greeny-blue shades are from indigo. The wool skeins were first treated in the rhubarb leaf solution, then dyed. No other mordant was used.

Following a comment on my latest entry on Rhubarb Root, I thought it might be useful to clarify the difference between rhubarb leaves & rhubarb root. Rhubarb root is a very useful dyestuff, more suitable for animal, rather than vegetable, fibres, & it can be used both with or without a mordant. Used with colour modifiers, it gives shades ranging from yellow & rust to pink, red-brown & green. It doesn’t seem to matter what species of rhubarb you use. I use the roots from the edible rhubarb I grow in my garden for pies etc. Some people use the roots of ornamental rhubarbs. The rhubarb root sold commercially often comes from China & is used as an ingredient in laxatives or purgatives.

Rhubarb leaves, which contain poisonous oxalic acid so should be handled with care, can also be used as a dye on mordanted or unmordanted fibres, but they tend to give only a pale yellow colour. Their main use is as an alternative mordant or base for other colours. They work well on animal fibres but are not really recommended for vegetable fibres. Rhubarb leaves are widely used as a base for other colours by Tibetan carpet weavers, working in Himalayan regions where chemical mordants are often difficult to obtain. They are also used to assist fermentation in indigo vats.

Full details for using rhubarb root & leaves can be found in my books. (See under “My Books”)

Using Colour Modifiers

Friday, December 12th, 2008

Full information for using colour modifiers is given in most of my books. For details of my latest book, “Colours from Nature”, see under “My Books” on this blog. Some information on modifiers is also given here in the entry “Colours from Dahlias”.

Basically, colour modifiers are used after the initial dyeing process to alter or modify the shades. So if you dye 5 skeins in the same dyebath, leave 1 skein unmodified, then apply a different modifier to the remaining 4, you will end up with 5 differently coloured skeins that all tone together. Modifiers may be pH alterants: acids like clear vinegar, citric acid, lemon juice; or alkalis like washing soda, soda ash or wood ash water. (See below) The other modifiers are solutions of iron or copper. A small quantity of the modifier is added either to a pot of water or to some of the used dyebath. The dyed materials are then added to these solutions (1 to each) & left to soak until a colour variation is achieved. If nothing much seems to be happening, just add some more modifier & continue with the soaking. Sometimes the colour variations are dramatic, sometimes they are more subtle & on occasions it’s difficult to notice much change at all, especially with acidic modifiers. In my experience, the most useful modifiers are the alkalis & iron. You can also heat all the modifier solutions EXCEPT THE ALKALINE MODIFIER. If you heat this, you may damage or even destroy animal fibres such as wool. BE WARNED!

NOTE: Wood ash water is made by removing the ashes from a wood-burning stove & soaking them in water for a week or two. The ashes sink to the bottom, leaving a yellow liquid which is strongly alkaline. You can tell when it’s ready because it will feel slick or slimey to the touch. Just remove the solution without disturbing the ashes & use half to one cupful as your alkaline modifier.

Rhubarb Root again

Thursday, December 11th, 2008

At last I’ve managed to find time to try out the colour modifiers on the rhubarb root extract dye that I wrote about earlier. The samples are on unmordanted wool.

The photo shows from top to bottom: No modifier, acidic modifier (clear vinegar), alkaline modifier (washing soda), copper modifier & iron modifier. (Note: I always put the modified samples in alphabetical order – acid, alkali, copper, iron). The last sample is from a different dyebath, made by adding an acid (this time citric acid granules, but clear vinegar would have been equally good) to the dyebath before dyeing. I added enough to turn the dyebath yellow, rather than rust, in colour. However, take care not to add too much or the colour may be too pale, so add it gradually.The unmordanted sample was then added & simmered for about 20 minutes. This latter method is a useful way of getting a clear yellow from rhubarb root, in either extract or plant form, without having to use an acidic modifer afterwards. If you dye several skeins in the acidified dyebath, they can be modified as usual, although little change occurs from an acidic modifier.

I was delighted with these results, as rhubarb root is such a useful, versatile dye, especially as it can be used without a mordant. It was good to know that the modifiers are effective when used with the dye in extract form.

Woad again

Tuesday, December 9th, 2008

 Today the weather is cold, dull & gloomy, so I just wanted to remind myself of that chilly but bright day in November when I made a final vat using my home-grown woad leaves. Here are some of the skeins I dyed that day, hanging outside to dry.

Stored away in my shed I still have some woad solution, to use whenever the mood takes me or when the brighter weather draws me outside to set up my dye pots.

Woad solution is easy to make & can be stored for several years. All you do is follow the instructions for using fresh woad leaves, given in my earlier entries, up to & including the whisking to produce the blue froth. Then leave the solution for a while to allow the froth to settle. It’s important to make sure all the froth is incorporated into the solution, as the froth contains most of the blue pigment. Then pour the solution into a strong glass or thick plastic airtight container with a well-fitting lid. (If you use a plastic container, make sure it is made of thicker plastic than those containers used for milk. I have found that, if the plastic is too thin, the blue pigment is absorbed by the plastic, which becomes a deep blue, leaving little pigment left to dye anything else.) Allow the solution to overflow slightly, then screw the lid on well.  You can add a teaspoon of sodium metabisulphite as a preservative if you like, but I’ve never found it necessary. I have successfully stored woad solution in my shed for several years & it never seems to develop mould or deteriorate in any way .

Using Woad Balls

Saturday, December 6th, 2008

The photos show (left) the vat with the blue colour beginning to emerge as the yarn appears above the surface & (right) the yarns with the blue dye developing.

 Last week Ian Howard, the woad grower from Norfolk, sent me a few woad balls to experiment with. Woad balls are rare nowadays & I believe they may only be available commercially from Ian. Of course, woad is simpler to use in powder form & it is only recently that woad powder has become available. Before that, dyers keen to use woad had to grow their own. Until the 1930s woad was grown & processed in England in the fens in East Anglia, not far from where I live. The woad balls were made by crushing the leaves to a pulp between rollers, draining off any excess liquid, then rolling the pulp into balls, which were laid on racks to be dried. Sometimes woad was traded as balls, which then had to be processed further into couched woad before they were ready for dyeing. To make couched woad, the balls were pulverised, sprinkled with water & left to ferment. During this period, the mass was turned frequently & large lumps broken up. Finally, this crumbly substance, known as couched woad, was dried & packed into barrels, ready to be sent off for sale.

But back to my woad balls. As I want to save some for a fermentation vat when the weather is warmer, I just used one for this test. I was surprised at the amount of blue there seemed to be in this one ball, even after I had been distracted by a phone call & let the vat simmer on the cooker – absolutely not a good idea! Not only that, the vat kept going over several days & didn’t seem to mind getting cold overnight & being heated up next morning.

Basically, as I wasn’t planning a fermentation vat, I followed the same procedure as I use for dyeing with fresh woad leaves, except that I left the leaves in the vat throughout. So first of all I broke the ball into small pieces by bashing it with a mallet (yes, woad balls can be very hard indeed!). Then I poured a little cold water over it to just cover the pieces. I did this as a precaution, in case “shocking” it with boiling water destroyed any dye potential, although I think it would probably have been OK to start off with the boiling water. Then I poured boiling water over the pieces, about enough water to make a small vat, & left them to steep for about an hour. I then strained off the liquid, added enough washing soda (sodium carbonate) to turn the liquid from brown to greenish & began the whisking process. At this point, I should say that the smell was quite strong but, as I love the smell of woad, it didn’t bother me at all. Also, the whisking process produced no sign of any blue froth but I decided to continue, as I seemed to recall having had this experience before. After whisking for about 15 minutes, I decided to return the pieces of woad ball to the liquid & then I whisked a little more – still no blue froth. I then poured the liquid, plus woad ball pieces, into a stainless steel pot & set it on my cooker. I heated it gently to about 50C/120F (or as hot as the hand can tolerate for a count of 3 – what I call “1,2,3 ouch!”) & then added some sodium hydrosulphite to remove the oxygen. After about 10 minutes, I decided to add some wool to see if any blue had developed & was delighted with the results. The first skeins were a deep blue/green, later skeins became a little paler, & one skein was a delicate green. The colours on the second & third days were just as strong as those on the first day – probably because leaving the leaves in the vat allows the blue to continue to develop as time progresses. This vat does not look like the usual woad or indigo vats; the colour of the liquid is a murky brown/yellow, although a blue metallic sheen does appear on the surface after a while, only to disappear again later. Neither does this vat give the same shades of blue as woad vats from fresh leaves or woad powder. The blues are tinged with green, so appear more turquoise, although this is not apparent from the photo above. (However, it’s very difficult to show colours absolutely accurately in photos, unless one has sophisticated equipment & considerable skill & I have neither, I’m afraid, being a complete novice where photography is concerned.) I imagine these colours are probably influenced by the other pigments present in the leaves, such as those that give the tan shades when woad leaves are used following the usual simmering method, & the green tones occur because the leaves remain in the vat throughout. I suppose I need to do another vat without the leaves in, to see what happens without them – perhaps at a later date. I also suspect that these greeny-blue shades may be closer to the blues our early ancestors achieved when using the fermentation vat method.

To sum up: Woad balls can be used in the same way as fresh woad leaves, except that the leaves should remain in the vat throughout. Whisking may not produce any blue froth but ignore this & continue as usual. The vat itself will not look like the more usual woad or indigo vats, but this does not seem to be of any importance. The vat can be kept going over several days & the colours from this type of woad vat will be more green in tone.

NOTE: Woad balls are available from Ian Howard, just click on the link under “My Favourite Websites”. Ian also has some excellent weld dyestuff available (not in extract form) which he has grown on the farm & madder extract is also on his list. (See picture below)

This picture shows:

From left to right: Madder extract (alum mordant), madder extract (alum mordant + washing soda after-soak), weld (alum mordant), weld (alum mordant + copper modifier), weld (alum mordant + iron modifier)


Thursday, November 20th, 2008

During my recent woad-dyeing session, I happened to dye a skein that had been mordanted with alum. I was interested to observe that this alum-mordanted skein dyed a greener, more turquoise shade of blue than the unmordanted skeins. I wondered how I had failed to notice this shade difference before. I can only explain it as follows: Usually, I use unmordanted skeins for indigo & woad dyeing, unless I am using indigo to over-dye a skein already dyed in a dye that requires a mordant. As I always use indigo as the last dye in a 2 or 3-dye sequence, I suppose this was the first time I had used an alum-mordanted skein that had not already been dyed. As to why I always use indigo as the last dye in a sequence – I think this is because the depth of colour from indigo is easier to control than the depth of colour from other dyes. So by using indigo as the last dye, I can dip for a short time initially & then build up the colour gradually. I usually also reserve the other dyebath, in case I need to add some more of the first dye after the indigo (or woad) dyeing process.

Woad Dyeing in November

Wednesday, November 12th, 2008

Unfortunately my woad plants were ravaged by caterpillars this year, so I wasn’t able to harvest my usual heavy crop of woad leaves for the dyepot. The best time of year for harvesting & using the leaves is from late August/early September to the end of October. This gives the leaves time to develop their blue pigment. However, I have successfully used leaves for the dye vat at most times of the year, so it’s always worth using any leaves you can find, no matter the time of year. Also, although first-year leaves are generally recommended for the strongest blues, I have managed to obtain good blues from second-year leaves.  Some of this year’s leaves were picked for a demonstration of woad dyeing in September at Denny Abbey in Cambridgeshire, where I regularly tutor natural dyeing courses. The last few remaining leaves were harvested this week in the pouring rain, ready for a woad-dyeing session with Chris Dobson, friend, fellow-dyer & plant expert. Fortunately, Chris brought with her some really large, “meaty” leaves to add to my rather pathetic specimens.

The blues Chris & I obtained from our dyeing session were as good as any from other sessions, so we were pleased with the results of our efforts. This is the method we used:

Collect about a bucketful of leaves, tear or cut them into small pieces, pour boiling water over them to cover them & leave them to soak for about an hour.  Then strain off this liquid into another bucket & squeeze the leaves well to collect all the possible colour potential. Next, add enough washing soda crystals to turn the liquid from brown to green. To incorporate oxygen into the liquid in order to “activate” the blue, the liquid must then be poured from one bucket into another until the froth turns blue. Alternatively, the liquid can be whisked well. The process must be continued until the froth no longer turns blue & this can take quite some time. But persevere, no matter how much your arms ache, otherwise much dye potential may be wasted. After this pouring process, leave the liquid to stand for a while to allow the froth to subside. Then pour the liquid into a stainless steel dye pot & heat until the liquid is so hot that the heat is only just bearable to the hand. (Approximately 50C) Then add 2 to 3 teaspoons of sodium hydrosulphite to remove the oxygen & leave the vat to rest for about 20 minutes. By this time the liquid below the surface should be greeny-yellow & the vat is ready to use. Remember it is important not to introduce any oxygen into the vat, so add the materials to be dyed very gently so as not to cause bubbles. Leave the materials to soak for 5 to 20 minutes, depending on the depth of colour required, then hang them in the air to allow the blue to develop.

NOTE: More information on indigo & woad dyeing can be found in my latest book “Colours from Nature”. For further details about this book & how to order it, look under “My Publications” or  email

Yew Tree Wood Shavings

Sunday, November 9th, 2008

While visiting The Manor at Hemingford Grey (see entry on Bracket Fungus for more details) I saw a wonderful spreading yew tree (Taxus baccata) in the secret garden. This reminded me that yew wood shavings can give lovely orange & rust colours in the dyepot. So if you know a woodcarver, or have some other source of yew wood shavings, collect about the same weight of wood shavings to fibres you wish to dye & start off by pouring boiling water over the shavings & leave them to soak overnight.

Then simmer the shavings for about 1 hour & pour off the liquid to make the dyebath. Use wool mordanted in alum – I usually use 10% alum i.e. 10gms alum to 100gms wool – & simmer the wool in the dye solution for about 30 to 45 minutes. Leave to cool before rinsing. You can also experiment with colour modifiers for variations in shade. (See entry on Dahlias for further details).

Autumn Leaves

Friday, October 31st, 2008

As I rustle through the autumn leaves as I walk through my garden, I am reminded of one way of using these leaves for a dyebath. Don’t expect vivid reds, but fallen leaves will often give attractive, rich brown shades that are useful as a contrast to more brilliant colours. I usually pack a bucket full of fallen leaves, fill the bucket up with water (or wait & let the rain do the job), then leave the bucket in a corner of the garden until I’m ready to make the dyebath. (This soaking will extract some of the colour potential from the leaves.) Then I just transfer the contents of the bucket to a dyepot, simmer the leaves for about 45 minutes, then strain off the liquid to make the dyebath. Use an alum mordant for the strongest colours or, if you prefer not to use a pre-mordant, use an iron after-bath to intensify & fix the colour. (The entry for Dahlias gives more details of using an iron after-bath.)