On Mordanting

 Blog

Indigo is apparently the gateway drug of the natural dye world. It led me to try dyeing with cochineal, which should have led me to a better understanding of mordanting, except it didn’t. There are a lot of recipes, but not a fat lot of information out there on the science of natural dyeing. There is a lot of information on synthetic dyes. As it turns out, there is a good reason for this.

The history of synthetic dyes is also the history of organic chemistry, so the process of learning how to make synthetic dyes provided the chemical knowledge. The advent of synthetic dyes squeezed out the natural dyers’ guilds, so the new chemical knowledge wasn’t applied backward. There is a lot of good information out there on the invention of mauveine, the first analine dye. If you love history, how synthetic dyes changed the socio-economic world is fascinating, and it in part explains why there is precious little textile manufacturing still done in the US. Some of the more interesting monographs I’ve come across about the chemistry of natural dyeing are from India, Pakistan and Egypt, where there still are textile industries, and where scientists are taking another look at natural dyestuffs in order to have a more sustainable and less toxic impact on their environment. I’ve ended up learning about synthetic dyes, color chemistry, the quantum physics of color, synthetic fibers, and finally, mordanting and natural dyes.

That said, Maiwa and Turkey Red Journal are both excellent resources for natural dyeing information, including the chemistry, and they are both on the forefront of bringing the chemical knowledge back to the natural dye world.

So what is mordanting? If you are using metallic mordants, basically you are making your own acid dyes. Instead of using an acidic bath to promote ionic bonding as with synthetic acid dyes, the metal ions of the metal mordants have a similar polar effect. The mordants form covalent bonds with the color bearing compounds in the dyestuffs, which are the very strong bonds between atoms (sharing electrons in the outer shell). Since they are acid (polar) dyes, they therefore bond better with the positively charged amino acid chains (wool, silk) and poorly with cellulose (cotton, linen).

Tannic acid is a non-metal mordant, but “tannic acid” itself isn’t really a discreet chemical, but rather a broad heading under which several acids fall (which also happen to be tannins): Gallic acid, ellagic acid, and catechic acid. Most of the so-called “substantive” natural dyestuffs that require no mordanting have some form of tannic acid in them, for instance, sumac, pomegranate, fustic and cutch. Tannic acids bond well with protein fibers (think tanning hides), and also with cellulose plant materials. It also bonds well with the metal mordants, so plant fibers normally get pre-mordanted with tannic acid, and then again with the metal mordant.

I really wish I could tell you what chemical bonds are formed between tannic acids and these different fibers, but I’ve had no luck in finding scientific documentation thus far. I have to assume it’s not covalent bonding with cellulose just because fiber reactive synthetic dyes are so much more wash fast. I’m starting a natural dyeing class in October and I’m hoping to get to the bottom of this.

Nowadays aluminum acetate is available to mordant plant materials and the tannic acid step is debatable—this post and this post from Turkey Red Journal do comparisons of dyeing cotton cloth with different configurations of tannic acid/alum/aluminum acetate. Some of their considerations are cost and availability for dyers in poorer countries. Rachel does most of the cotton dyeing between the two of us, so I’m leaving it to her to take good notes on her findings.

This monograph is great in detailing the chemical structure of wool. There is a lot going on in a strand of wool, aside from the positively charged dye sites. There are other chemical bonds that give rise to it’s strength and elasticity, and these are both things that can be affected by Ph, heat, and specific properties of different metal mordants like iron or tin.

There is a time vs. temperature factor in mordanting. A lot of recipes call for simmering your wool in your mordant for an hour, but that can easily lead to felting. Heating up your mordant and letting your wool steep overnight can often produce a more thorough saturation of the fiber and therefore more even dye uptake. Mordanting can take place before, during, or after the dyeing, but if it’s done prior to adding the fiber to the dye pot, there is more control over the mordant-to-fiber ratio, and the mordant bath can continue to be reused. This becomes more important when using the more toxic of the metal mordants, tin, copper and chrome.

Older mordanting recipes called for an excess of the metal mordants to ensure good dye uptake, in part because the strength of the mordant material was not guaranteed. Now we can source mordants with guaranteed strength and purity, so we can be a lot more precise and use recipes that leave little to no extra mordant in the bath. I did some trials with cochineal earlier this summer (that’s the next blog post). Using a recipe for a weighed amount of fiber, I tested my mordant bath to see if it was actually discharged (my copper did not seem to be), by adding more fiber to the “discharged” mordant bath and then soaking it in the dye bath and seeing if the dye strikes or not. When I was done I bottled up and saved my remaining mordant bath rather than tossing it out anywhere.

On hold for the next round of mordanting

Once the mordant has bonded to the fiber it’s not going anywhere, so you can use different mordanted materials in the same dye pot, which is fun and interesting because you can see the effect the different mordants have.

Some metal mordants are toxic. Chromate poisoning is particularly unpleasant. Oxalic acid, often used to shift colors as an after-mordant is toxic. Synthetic “true black” acid dye is also toxic, as it contains chromium as it’s coloring component. None of theses things belong in the groundwater, or your septic tank, or near kids, pets or livestock. Entrapment is the state wherein metal particles are trapped in the steam from a water bath, and are then able to be inhaled, so don’t mordant in your kitchen. And for that matter…

Oak galls

A cautionary tale: we have a large tanoak tree growing next to the abandoned well out by our barn, and as a good source of natural tannins, I checked the interwebs for what the tannin concentration should be compared to oak galls, etc, for a possible recipe. What I found was that it wasn’t a tanoak. So I used a tree identification website rather than the book with illustrations I’d used initially, and the final question on the flowchart was “do the leaves smell like almonds when crushed?” Ironically as it turns out, this reminded me of the opening lines of Love in the Time of Cholera. My tree does smells like almonds when the leaves are crushed. It’s a cherry laurel, and when you boil the leaves you get hydrogen cyanide, which Nero used to poison his enemies’ wells. So. Back to collecting gall nuts.

The Science of Dyeing

 Sally Williams

 Blog

What is color? When I studied philosophy as an undergrad, it was always treated as a “secondary quality”, that is, something that’s not intrinsic to the nature of the thing itself. And while it’s true that how we see color is a subjective function of our eyes and processing in our brains, the colors of things is entirely dependent on the physical makeup of those things. When we see color, we are seeing into the atomic and subatomic nature of things. In other words, a tree is green in a forest even if no one’s around.

To understand how color works, you need a little quantum physics. This monograph on color chemistry is concise, well-written, and with a little patience, accessible even for people like me who have only high school level chemistry and physics. If you are at all interested in how dyeing works, it explains everything.

I’m also slogging through this one. It’s highly technical and I can only digest a few pages at a time, but it details all the general information in the first book. If you want more after reading The Chemical History of Color, then this is for you.

To very generally sum up, the visible spectrum that our eyes can detect takes place in a really small range of wavelengths, from red to violet. Everything of shorter wavelength then the red range is the infrared, and everything longer than the violet is the ultraviolet. How these wavelength are generated or influenced happens at the quantum level, with the interactions of the electrons within an atom or a molecule. The electrons need to be understood as waves, not particles as I learned in high school chemistry. There are four or five different models that explain wavelength production, depending on the arrangement of electrons in their shells around the nucleus, and how they combine, or don’t combine with other atoms. What’s neat about all of this is that our eyes are seeing what’s going on at the quantum level! (That’s my take on it. I can’t think of any good reason why humans spend so much time and effort changing the color of things, if not to influence the building blocks of the world itself.)

Natural dyeing shows us that there are some plants and insects that impart good, lasting color, and some that are fugitive. The beginning attempts at synthesizing these color compounds were all trial and error, but now computer modeling can predict what wavelengths a particular molecular configuration should yield, and how to bind it to a particular fiber. It should be noted that two things dyers care about, light-fastness and wash-fastness are two separate issues. Light-fastness depends on the ultra-violet spectrums’s influence, whereas wash-fastness depends on the type of bond with the fiber (for the most part). Ultraviolet wavelengths can greatly influence the visible spectrum. We see this when colors fade in the sunlight. This often comes into play in natural dyeing (with black beans and berries for example)…one of the advantages of synthetic dyes is that they’ve been designed to be less susceptible to this effect. Another advantage of synthetic dyes is their leveling ability, that is, to dye evenly. They’ve been designed to bond weakly with the fiber so that they can actually un-bond and re-bond, rather than strike all at once in a concentrated area. Some of the molecules used to produce color are quite large, especially in the blue range. This is why even when using an acid dye, there is still blue left in the dye bath even though it is fully exhausted. The color producing part of the molecule is so large that it will actually break off from the part that bonds to the fiber during the leveling process. One of the mysteries of indigo is how it’s able to produce a blue color out of a relatively small molecule (there are several theories).

Synthetic dyes are often described as brighter than their natural counterparts. This is because the synthetic dye molecule is emitting a vary narrow, specific wavelength, where a natural dyestuff, as a complex plant material, is emitting a broader range of wavelengths within that color band. Different mordants also affect the color in natural dyeing. The metals used in mordanting not only have the necessary number of electrons in their outer shells to form covalent bonds with the dyestuffs, but of themselves have different wavelength properties…precisely because of how the electrons are composed around the nucleus of the atom. (This website/app of the periodic table is great. It shows everything you might want to know about each element, down to the electron spins in each orbit.)

Color aside, to understand how dyeing works, you need chemistry: the chemistry of the fiber being dyed, and the chemistry of the dye. Here are two excellent blogs that explain the chemistry of synthetic dyeing in simple terms:

Gnomespun Yarns

Paula Burch’s All About Hand Dyeing

Again to sum up, there are different types of bonds that can be formed, and they depend entirely on what you are dyeing: the amino acid chains of proteins, or hydroxide chains of cellulose plant material, maybe a mixture of both in the case of synthetic fibers, (or none of these in the case of polyesters). Animal fibers have positively charged receptor sites, so ionic bonding occurs with acid dyes (and also some hydrogen bonding, which is like ionic bonding but smaller). Plant material’s OH hydroxide chains don’t have the positve charge sites that animal fibers do, so fiber reactive dyes are designed to form covalent bonds, which are very strong, in a basic, rather than acidic bath. Disperse dyes dye plastics at high temperatures and pressures, although there are disperse dyes available for the home dyer that work in the dryer. Direct dyes work through a force called substantivity, and they need to be rather large molecules in order for this force to work. Since they are so large they are not particularly wash fast, and the colors are often duller. They are generally used on plant fibers, and are a component of all-purpose dyes like Rit.

This post by Gnomespun Yarns does a good job explaining the difference between animal fibers and plant fibers, and how it affects dyeing. This one by Paula Burch does a good job explaining the different types of chemical bonds that are made with the various types of synthetic dyes. They are both well written, with nice diagrams, and really explain why it’s important to know the chemistry of what you’re trying to accomplish.

All of this is by way of the next blog post, which is about mordanting. The chemistry of natural dyeing is only very recently becoming well documented, and I’ve found that understanding the technology that succeeds it is the most straightforward way of getting to it’s precursor.

But is it yarn?

 Rachel Wolcott

 Blog

Art yarn?

Ah the allure of Art Yarn. Behold its super-chunky sparkle, its beads, its coils and luscious locks. Resistance is futile. Or is it?

When I started to spin I announced to Sal that all I wanted to make was art yarn. I probably told her I wanted to explore colour and texture. I was making it up.

Sal told me something like this: If you’re ever planning to make anything like a sweater or a wearable garment you should think about making less-arty yarn.

She had a point.

These days I think about hand spun yarn completely differently. What I used to consider art yarn, I now classify as novelty yarn.

Most of the time I’m experimenting with new materials and techniques. I’m spinning to weave or to knit. My use of art yarn is sparse. That’s partly thanks to my fairly boring sartorial habits. Sal tells me that’s a trend now! Yay!

So what about art yarn?

Last month Alison Daykin gave my guild a talk on art yarn (see below). Beforehand I was curious what she would have to say and it got me thinking. What is art yarn? Is it yarn for yarn’s sake? Is it a novelty item? Does anyone actually use it?

I still make a lot of art yarn, but I call it handspun. Like most spinners I’m experimenting with colour, texture and gauge. Most of it isn’t sparkly or bejeweled. The excitement is in the color or the materials.

Here’s some sport weight yarn I made for a weaving project.

Blue yarn

The blue colorway is a combination of natural coloured and dyed fleece.

The red is a blend of acid and natural-dyed fleece as well as natural coloured. To me these are rich in colour and texture. I’ve made little aesthetic decisions throughout the making process.

Red yarn

Is it art or is it yarn?

These are some examples of what are more commonly considered to be art yarn. There are the dyed locks, the thick/thin look and some bouclé-like yarn.

Bouclé, sort of

Thick thin

Yarn or art? Both?

Lexi Boeger sees it this way: “I believe the onus is on the buyer to look at the yarn and be able to determine an appropriate project to use it for. This puts more work on the buyer, but ultimately it will make that person also more creative..” (See Spinartiste)

Boeger goes on to say that art yarn can help the knitter (or weaver for that matter) think beyond the pattern and become a designer. My reading of that is: art yarn can be a starting point. It asks the question: what can you make with me?

It’s worth pointing out that Lexi Boeger isn’t making art yarn anymore.

Locks

JazzTurtle has a long list of patterns that can use art yarn. But to me art yarn is perfect for weaving–especially saori weaving, which is all about experimentation and personal expression. It’s not really concerned with pattern or convention.

This saori-inspired piece uses some art yarn. For me this piece was a big departure from the norm. Here are colours and textures far from my comfort zone. It marks a step in a creative journey, but I’m not sure the path ends at art yarn.

Weaving with art yarn

[Sal here. I’m going to horn in on your post for a minute]

I would argue that handspinning is technology, and as such there is an intrinsically practical component to the resulting product. Some yarns take a good deal of skill to make well (bouclé for example), or have aesthetic consideration in their colors or textures (as yours do above), and this intersection of technical skill and aesthetic consideration I would call “craft”. Calling something “art yarn” is almost oxymoronic. Yarn for yarn’s sake, as you say, really makes no sense— like building a chair that you can’t sit on. But I know plenty of people who spin and never do anything with the yarn because they don’t knit or crochet or weave, and are perfectly happy that way. I suppose there is a Venn diagram we could make that shows the people who like to build chairs, but don’t actually sit down. I think one could certainly make yarn that’s an end in and of itself, and it could be considered art instead of artisanal, but I think the intention behind it is key, because it would be subverting the concept of yarn. The rest, as you say, is novelty yarn. I’m curious what your guild speaker had to say on the subject. And if they have any good patterns.

[Now back to our regularly scheduled blog post ;)]

Fancy Yarn and permission to spin

When Alison Daykin came down from Derbyshire to talk to the Mid-Essex Guild about art yarn, like Sal I was curious what she had to say about art yarn. One reason for that curiosity was I suspected [knew] many guild members were dubious of art yarn. Many–not all–take the view that art yarn is what you make when first learning to spin. “Don’t worry,” they tell new spinners. “You’ve just made art yarn!” And then everyone laughs.

Alison Daykin described what she makes as fancy yarn, not art yarn. Fancy yarn, Alison explained was any kind of yarn you made that’s non-standard–core spun, bouclé, crepe, thick/thin–that has some irregularity in the making. That irregularity could be introduced in any or all of the steps for making yarn: prepping fiber, color blending, spinning and finishing.

According to Alison, fancy yarn isn’t anything new, in fact Mabel Ross, author of The Encyclopedia of Handspinning, was an early advocate of fancy yarn. However, when Alison started spinning in the late 80s/early 90s she felt spinning non-standard or fancy yarn was discouraged. She was taught that the point of spinning was to churn out yards and yards of yarn that looked like it had been made in a mill.

“I wanted to make different yarn and I felt inferior, because I didn’t want to spin plain yarn,” she said. But after taking a course on spinning and dyeing for tapestry weaving from Bobbie Cox, Alison felt she had, “Permission to spin whatever I wanted. Once you know the rules, you can break them.”

Art yarn, Alison said, is a term that grew out of a trend of making yarn out of recycled materials like plastic bags and cassette tape. She did not see the point in putting yarn in a bowl or hanging it up to admire.

“If I can’t use the yarn, then I’ve wasted my time. Use it to make a garment look different. If you use a little yarn in a piece, it can look lovely. Art yarn has got to be practical as well as beautiful,” she added.

The Indigo Fruit Vat: La Technique

 Sally Williams

 Blog

I recently took a class at the Oregon College of Art and Craft, on how to create a quick, environmentally friendly indigo fruit vat. This method was developed by Michel Garcia, a French chemist, botanist and natural dyer. This post is how to go about it. This other post tells you why it works.

The recipe is very simple: 1 part indigo, 2 parts pickling lime, 3 parts fructose, by weight. If you want to use powdered fructose, you just weigh all your ingredients out on a scale.

We used apple juice— cooked-down, mashed apples in water. Any sweet fruit will work, as will dates, or agave or honey, anything with fructose. The only thing not to use is citrus, which will change the Ph of the solution.

By volume, we filled the stockpots we were using about 1/4-1/3 full, then added warm tap water to about 2/3-3/4 full. From the approximate measurements, you can see that the fruit vat is very forgiving. The apple juice was hot and the tap water warm. A warm vat is desirable, but not over 140F, or the chemical reactions won’t take place. The amount of water is not important, other than to have enough space to dye under, because it must all be done below the surface.

Next the indigo is added. We used 20g of powdered indigo for our stockpot. Since indigo is insoluble, it’s hard to stir in without either agitating (i.e. adding oxygen) the pot quite a bit, or having it sit on the surface. To get around this, we put the indigo and some water in a small mason jar with marbles and shook that mixture around vigorously for a few minutes, essentially making a slurry. That was then carefully poured down the side of the pot, to again, minimize the amount of air being introduced into the vat. Any indigo left in the mason jar was swirled around with more water and added as before.

Then we added the pickling lime, also hydrated with some water, and again, carefully poured down the side of the pot. Since we used 20g of indigo, we used 40g of pickling lime.

Then everything was given a good stir. By this I mean creating a vortex in the center of the pot, but not so much to be adding air back in. Once a good swirl was going, we held our spoons still against the side of the pot and let everything swirl to the center. At this point any oxygen bubbles come to the surface in the center of the pot. This is called the “flower”, and if the vat is working properly it should be a deep blue. The vat itself will be a clear greenish-yellow, and it will form a skin on top.

Indigo fruit vat flower

We let the vats sit about an hour for the fruit solids to settle in the bottom of the pot, and for the reducing process to take place. However, out instructor dipped a piece of cloth into her vat about 5 minutes after she stirred hers, and it was already turning a light blue. It’s very fast!

As for the dyeing itself, it must be done below the surface of the liquid, to keep the oxygen out. The fiber should be wetted in warm water prior to dipping, again, to replace the air molecules in the fiber with water molecules. Dip gently down the side of the pot, and hold underneath for at least three minutes. YES WEAR GLOVES! Indigo doesn’t need a mordant, so you will dye your hands, too. During this time massage the fiber. This helps move the indigo into the fiber. As our instructor described it, “Indigo is a large, slow moving molecule. Give it some help.” Depending on what fiber is being dyed, it may be more or less tolerant of the alkaline solution it’s in. Cotton doesn’t mind, but silk and wool can be damaged from too long of contact— they can lose their luster. This is why traditionally cottons are dyed first, then silks, then wools. As the vat is used, it becomes less effective and also less alkaline. Because of the fiber structure of wool, it requires less of the indigo to achieve good color.

After your three minutes or so, bring the material out of the dye vat, and quickly hold it over another bowl to drip in. Any drips back into the vat also add air. Then you must expose the areas that you wanted dyed to the air, so that the indigo re-oxides and forms it’s electrostatic bond with the fiber. You will see it turn from yellow to green to blue, as this process happens. The rule of thumb is to have to material exposed to the air for at least as long as it was in the vat. If the material doesn’t oxidize, it hasn’t been dyed. The other rule of thumb is that at least three dips into the vat a required to achieve a good color. Each subsequent dip happens in the same way, with airing out in between.

Making sure to air out between the folds for good oxidation

The materials you have dyed will be lighter once they’ve dried, so it’s best to get it darker than the final result you want. Each dip in the vat adds another layer of indigo to the material, so it will be more colorfast than just one dip.

Once the color is to your liking, rinse the material and let dry. If it’s wool or silk, soak in a vinegar/water solution to return the Ph to the liking of the fiber, then soak in a mild soap and water, and rinse. Rinsing is only removing the indigo that didn’t bond to the fiber.

The indigo water that runs off from the dyed material in the vat has been oxidized, so don’t add it back to the vat.

Using an indigo vat can only happen for so long before it stops working. This is not because the indigo is used up, rather, it’s because each “dip” into the dye vat also re-introduces oxygen, so the indigo becomes unavailable again, and there’s not enough fructose left in the vat to get the chemical conversion going again. When you are done for the day, add more fructose to your vat, and you can check the Ph with a Ph test strip. It should be around 9-10. If it’s lower than that, add more pickling lime.

When you want to use your vat next, add more fructose, stir the vat again and let the flower come to the surface. It should be dark blue. If you’ve used the vat a few times and the flower is light blue, you will need to add more indigo.

If you want to dispose of your vat, whisking air (specifically the carbon dioxide in the air) in will turn the pickling lime into calcium carbonate, aka chalk. You can go ahead and water your plants with this. Maybe a nice indigo plant.

Indigo-a-go-go: Better Dyeing through Chemistry

 Sally Williams

 Blog

I recently took a class on making an indigo fruit vat. The class was great, the vat is quick and easy and you can read how to do it here, but when it was over I was left wondering what’s going on in there?

The interwebs are sort of helpful, in that you can read all about what happens in the indigo dye process, but there appears to be an underlying assumption that dyers aren’t interested in the chemistry behind what they’re doing, so there’s not a lot out there that puts it in layperson’s terms. And they tell you chemically what happens, but not why it happens. Personally, if I know how a process works, I find it a lot easier to do the steps involved correctly, because it makes sense why all the steps are there. If I’m trying to get a bunch of molecules to do what I want them to do, it will be more efficacious if I’m not bumbling around blindly.

So I’ve spent a good amount of time looking for answers to this question, and what I ended up finding was that the ways and means of indigo extraction and dye methods mirror a lot of other human technologies— in the automotive world I call it the Technology of the Day.

This is indigo:

This molecule is not what is found in indigo-bearing plants (and snails!). True indigo (indigofera tinctoria) and woad, for instance, each contain different indigo precursors— molecules that will turn into indigo once they’ve been oxidized.

This is indican:

This is the precursor to indigo found in the indigofera tinctoria plants. The bow-tie shape is a glucose molecule.

This is indoxyl and this is what actually penetrates the fiber in the indigo vat. The bow-tie shaped glucose has been removed:

When making an indigo vat from fresh plants, all that needs to be done is remove the glucose part of the indican, and you get the smaller indoxl molecule. This is what will penetrate the fiber, and then turn into indigo with the addition of oxygen. Putting the fresh plants in a vat and fermenting them will remove the glucose, because the yeasts from the fermentation will eat the sugar part of the molecule and leave the indoxl behind. Here is a not only a nice article about different indigo precursors, but also a step-by-step tutorial on how to dye with fresh woad.

The indigo can also be precipitated out at this point instead of attaching it to a fiber. This will be the powdered indigo. The main thing to keep in mind is that once it’s been oxidized, it’s all the same indigo molecule; even synthetic indigo is identical. (*Mostly. I’ll come back to this later.) There is a lot of socio-economic history surrounding the trade and use of indigo, and it’s really fascinating, and I recommend this book which lays it all out in great detail:

The turning of soluble indigo-precursor plants into insoluble indigo is where we then go. The indigo can be moved around and traded rather than be tied to the place and season of the plant material. But it’s also one step forward, two steps back: that indigo molecule is not soluble in water. The indigo precursors in the plants are soluble, but in order to make indigo soluble, the oxygens on the indigo molecule need to form other bonds. The indigo needs to be turned into indoxl, then it can be worked into the fibers to be dyed. When the fiber in this dye bath is taken out and reintroduced into the air, lo and behold it oxidizes— it takes up the oxygen molecules from the air and turns back into the insoluble indigo molecule, where it is held fast by electrostatic bonds within the fiber. The best technical description that I found of how the indigo molecule bonds with fiber can be found here.

There are actually a lot of ways to go about making indigo soluble, and they all involve a reducing agent and an alkaline solution. This is the indigo vat. There are a lot of reducing agents, some of them very effective, and also toxic. For instance, here’s the process for dyeing jeans. A reducing agent has free electrons that are readily available to bond with any oxygen in the vat, whether it be on the indigo molecule or oxygen from the air.

Indigo vats need to be alkaline. An alkaline solution simply has more OH ions than H ions:

I couldn’t really find any good descriptions as to why the vat needs to be alkaline— what work are those OH ions doing? I ended up calling my brother in-law, who has a degree in chemistry: a reducing agent adds it’s electrons to form other compounds, so the oxygen bonds on the indigo are transferred and form alcohol chains with the reducing agent. Alcohols are very water soluble. The OH’s in the alkaline solution strip hydrogens off this alcohol group and we end up with the indoxyl. The OH ions are highly reactive, and essentially make the solution even more soluble. The more OH ions, the stronger the alkaline solution is (and the more careful one needs to be in using and disposing of it).

As there are a lot of reducing agents, so there are a lot of ways to go about this reduction, and you can see echoes of the original use of indigo-precursor plants: Fermenting urine is a tried and true method, because the ammonia in urine is already alkaline. Another traditional method is fermenting madder root and bran with soda ash or lye. Fermentations, aside from eating sugars in the original vats, also produce sulfur-containing organic compounds as by-products, which are effective reducing agents. As with any fermentation, you are relying on a process that involves time, often days, at a constant warm temperature. Not only do you have to wait to do your dyeing, but you must rely on a successful fermentation process. Commercial denim dyeing uses very efficient but also much harsher solutions, to the point where repeated dips in the vat need to be carefully timed so that the oxidized indigo already on the denim doesn’t get re-reduced and therefore removed again from the fiber.

I’ve made soap, and I’m not a big fan of dealing with lye, so I’d prefer a weaker base. I’ve successfully made an indigo vat with the madder root and bran, and washing soda which has a weaker Ph than lye. It took about 10 days to be ready to use, and it’s, shall we say, a little stinky. This is the Technology of the Day part: how to get the result you want as cheaply and easily as possible. Cheap and easy are relative terms— for instance, what’s the cost to the environment, or the person using a highly alkaline solution? When you are done with the vat, how are you going to dispose of it? As a home dyer, you can make these choices for yourself.

The fruit-vat method that I learned uses fructose from cooked-down fruit, which are reducing sugars, and pickling lime (calcium hydroxide) to make the solution alkaline. Fruit sugars are an expedient way to make a vat because they have free electrons available at the end of their chemical chains, and so are oxidized rapidly. Interestingly, sucrose, table sugar, will not work. Sucrose is a combination of glucose and fructose, but the way that chemical bond is formed takes up the free electrons at the ends of both chemical chains. Sucrose is not a reducing sugar. But water boiled down with fruits, dates, or honey and agave, all work well, and of course powdered fructose. Citrus doesn’t have a lot of fructose anyway, but the acids in citrus are also going to also going to make the vat less alkaline, so it’s not recommended.

So the sugars bonds with the oxygen, then the OH from the pickling lime reacts with the resulting molecules. Eventually the reducing agent gets used up: the sugar is turned into an acid and so is no longer a reducing agent. Addition of acid will change the Ph of the vat. The enemy of the indigo vat is air, because that re-introduces oxygen into the vat, which turns the indoxl back into indigo, and uses up the reducing sugars. Less introduction of air into the vat means a longer dyeing session. The vat needs to be kept warm, so that those molecules move around and react with each other, but not so warm that the reactions don’t take place. (The traditional fermentation vats would be at the right temperature anyway, to maintain the environment for the yeasts and bacterias.)

*So it should all be the same color if it’s all the same indigo molecule. Yes. Except if the indigo is precipitated from a plant source, it’s not going to be 100% indigo. There will be other molecules from the plant and the surrounding soil in there as well. Depending on what they are can change the appearance of the color. Also, depending on what fiber is being used the color will appear differently, because of the way that indigo bonds with the space within the fiber. If it’s lustrous like silk or matte like cotton it will appear differently. Depending on how alkaline the solution is, the protein fibers of silk or wool can be damaged. Depending on how well the fiber is worked in the vat will also effect how the color appears, based on how thoroughly the indoxyl is actually worked in or not.

I’ve spent about a month since my indigo class trying to get answers to my question, and I finally feel pretty satisfied that I’ve learned what I wanted to know. This process has also shined a light on the fact that so many natural dye recipes are just that, recipes, without divulging the science and available technology behind them. My hope is to demystify the processes so I can dye with confidence and reasonable expectations. Cochineal, you’re next!

Plying is Blending

 Sally Williams

 Blog

Malabrigo Nube roving Indiecita colorway

During my candy-dyeing experiment, I made roving that I was pleased with, but once I’d spun it and plied it with itself, I didn’t like the resulting yarn. I couldn’t find anything on the interwebs about how color changes through plying the same colorway. There are numerous examples of plying with neutrals, and there’s this nice Knitty article about how color changes when drafting vs. plying. So this experiment is to try and sort out how color changes through plying within the same colorway.

Here’s my singles laid out for plying: (from left to right) a single, chain-ply three-ply, two-ply, and three-ply.

Singles for plying

Here they are plied:

Roving, single, two-ply, chain-ply three-ply, three-ply

The three-ply appears obviously different. But the proof is in the pudding (or as Rachel says, the proof of the pudding is in the tasting), so I did some swatching:

Single ply yarn

I didn’t really enjoy spinning this roving because it was a bit felted and didn’t draft very well. This resulted in a slubby single, but knit up I like the texture the slubs add. The colors and striping are the same as the roving. So if I like how it looks as a single, any plying is going to modify the colors and texture.

Two-ply

This swatch ended up being the most dynamic, color-wise. The areas of high contrast (the yellow bits) give it a marled look. Depending on the project, this could add a great deal of interest, or just make it busy. There is some color striping but it’s pretty random. The areas of low contrast, with blues plied with each other, are less vibrant than the same color in the single.

Two-ply close-up: muted blues

Two-ply close-up: marled yellows

The chain-plied three-ply I expected to maintain the striping of the single swatch, just with thicker yarn, but the plying softened the color changes, and actually muted the colors:

Chain-ply three-ply

I picked the three most contrasting singles for the three-ply to try and get the maximum color variation:

Three-ply

The color changes have been blended out, so while there are areas of different color, the overall effect is a very gradual shift. Except for one spot where all the slubs lined up, the slubbiness is gone too. I have an automotive background, so this really reminds me of a three-phase alternator, so made to cut down on the low-spots in alternating current and provide a smooth, constant flow:

It’s all about the math!

So: when plying with the same colorway, the ply is going to change the color. A two-ply will only have half of each each single, a three-ply will only show a third of each single. I definitely should have swatched the single I’d spun from my candy-dyed roving to see if I liked it as-is. Swatch early, swatch often!

Onion skins, madder & gorse blossom

 Rachel Wolcott

 Blog

Onion skins

Natural dyeing is something I’ve wanted to try since one of my fellow guild members —Jackie Crook–gave a talk and demonstration last year. I’ve been saving onion skins, trying to grow woad, looking out for natural dye stuff as I’m driving through the Essex countryside. A few weeks ago after the first gorse blossoms appeared I got out my dye pots and started thinking about a dye garden.

I’ve borrowed Jill Goodwin’s A Dyer’s Manual from the guild library. I followed her instructions for mordanting–I used Alum–and dye stuff to fiber ratios. I soaked madder, made a gorse blossom liquor an

Melon color from madder

d boiled up some onion skins.

simmering gorse blossoms

I used some White-faced Woodland and fawn-colored Shetland fleece as well as some BowmontXDorset (BoDo) and angora yarn to test.

The BoDo/Angora could have used a little more dyestuff to bring out a deeper red color. Next time I’ll be more careful about my dyestuff:fiber ratio.

top: gorse, bottom: onion skins

I was most excited by the onion skin result on the fawn-colored fleece. I gave a brilliantly rich green/gold/brown tone. The onion skins dyed the white fleece a lovely brown/gold.

Onion skins with two colors of fleece

The effect of the gorse blossom was much more subtle. The white fleece took on a soft lemon tone and the lighter parts of the fawn fleece did too.

One reason–apart from lack of time–I hadn’t gotten into natural dyeing was I thought mordanting the wool would be a pain–it wasn’t. I also wondered whether natural dyeing could possibly yield better results than acid dyes.

Well. Natural dyes yield much subtler tones. You’re not going to get fancy multicolored roving using this method. And that’s OK.

What about the dye garden? Well madder, woad, weld and polygonum tinctorium (indigo) seeds have been found. It’s still too cold to plant anything here, but the ground is being prepared.

Guild Challenge: The Electric Kool-aid Fiber Test Results

 Sally Williams

 Blog

The test results are in! At our February Guild meeting, everyone brought their projects from the Kool-aid dye challenge.

Here are the winners, as voted by the Guild members:

Leaf shawl, from different strengths of yellow #6, then overdyed to mitigate the obvious stripes. Lovely.

Leaf shawl, from different strengths of orange, then overdyed to mitigate the obvious stripes. Lovely.

Saori scarf woven on rigid heddle loom, using blue and red dyes for a purple effect.

Grand prize winner. All colors used. Too adorable!

Here are some examples from people who have dyed with Kool-aid before, and know that it takes a lot of dye to get a lot of color:

Child’s jacket made from mitered squares. Love the intense colors.

“Sunset Colors” yarn. The turquoise shade is great.

Knit cowl. The charcoal grey tones down the vibrant colors.

Sophisticated roving with color blending.

A pair of green and blue hats.

Here are some examples of using less dye to nice effect:

Knit cowl with pastel colors and grey alpaca for a tweedy look.

Nuño felted sky blue cloth with lavender undertones.

Tea cozy topped with knit flowers, which were hand painted with Kool-aid, just as one would marzipan.

Some excellent examples of blending with neutrals:

The same hat-and-mitt set, two ways.

Knit socks, blue and orange. The heathered blue tones down the orange.

Felted bag with sheep. Lined and reversible!

What did I end up doing? My initial attempt at using Kool-aid ended with yarn that I hated. I went off on a tangent and dyed a lot of fiber with candy. I made this project bag. I got Spinner’s Block. I got over it. And in the 11th hour, I spun and dyed this:

Targhee two-ply, dyed with a jawbreaker, tic-tacs and sprinkles, then gradient dyed with red-to-blue Kool-aid.

I didn’t win, but I learned a lot, including an appreciation for dying spun yarn, not just wool. Up next: bring on the natural dyes!

Nuno felting part one: rub n’ roll

 Rachel Wolcott

 Blog

Nuno felting is one of those techniques I’ve always admired and wanted to try, but never got my act together to do. A couple of months back I bought Felt Fabric Designs by Sheila Smith and again my interest in nuno felting was piqued.

I was particularly interested in some of the techniques Smith shows “laminating” fabrics using felt and also upcycling thrift store scarves and fabrics into felted patchworks.

But I haven’t tried any of those techniques yet. Usually I dive in and try techniques even if they’re a bit complicated, but this time I tried some of the simpler nuno felting processes.

After a rummage in my closet I found a scarf I’ve never worn. It’s an open weave and 100% silk–ripe for nuno! Here it is on the table before felting. It’s on a strip of bubble wrap. I’ve spread light layers of Wensleydale roving and silk fibers on top.

100% silk open weave scarf readied for nuno

The next step was to cover with an old net curtain, wet down with cool water, smooth some olive oil soap over the net curtain and begin to rub!

My good friend and avid felter Gaynor was on the scene to offer advice and lend her fingers for rubbing!

Gaynor flipped the fiber-covered side face down onto the bubble wrap to give it a little extra rub

The bubble wrap provides the friction to felt the fibers into the silk scarf. Rubbing the fabric and fiber through the net curtain starts the felting process. Once you can peel the netting off without the fibers sticking to it, you remove the netting, place another layer on top then roll it up and begin to roll.

Gaynor’s tip for rolling the fabric in the bubble wrap was to roll the whole thing in a towel and roll it and then roll it some more. We didn’t keep an accurate count but I’d guess we rolled it a few hundred times in each direction?

What do I mean by rolling it in each direction? Well, once you roll your piece of fabric a few hundred times, unroll the bubble wrap bundle and re-roll it from the opposite direction and start the whole process again. It’s good to have a friend to help with the rolling if your arms get tired or you get a bit of finger ache.

Once you’re satisfied the fiber has mingled (or stuck) to your fabric give it a rinse in very hot water. Wad it up in a ball and throw it into the sink a few times. Then rinse with cold water. Take a look at your fabric. Have the fibers you’ve applied felted into it as much as if you would like? If not, give it a few more rolls in the bubble wrap and then the repeat the hot/cold rinses and throwing process.

Gaynor and I found that with this scarf, silk felted really well but the Wensleydale took a lot of persuading. If you’re after a shiny or even metallic effect go for more silk, less wool. Once the fabric is dry give it an iron, which brings out the silk’s shine.

Here’s my final product. I love how this technique has turned a drab unworn scarf into something I’m now wearing all the time. Interested in some amazing nuno felting? Check out the Sheep Cabana Pinterest board.

Finished scarf: drab to fab!

From fleece to fair isle, part 1

 Rachel Wolcott

 Blog

Fair isle is trendy

For at least 18 months I’ve been telling Sally how trendy fair isle is. “It’s so trendy,” I say. “Look at how many fair isle designs are in the magazines!”

In theory, I love fair isle. The the colors and miniature designs are enchanting. I’ve bookmarked loads of fair isle patterns on Ravelry and I’ve amassed a pile of magazines full of patterns. Alice Starmore’s Book of Fair Isle Knitting is on my shelf and I’ve mentally knit every Kate Davies pattern. Mentally. I admit I’ve bought a few fair isle sweaters to soothe the fair isle itch.

I’ve knit a couple of fair isle items, but spinning yarn to knit up in fair isle intimidates me. Getting the gauge and color right just seems hard, especially if I were doing a whole sweater. So I’ve put it off.

Until the other day when I was beset by a fit of madness. The sun was shining and I set up the drumcarder on a table in the garden and started cranking out some batts. The idea being to spin up some yarn to make two fair isle hats.

Now the question is how do I turn this hodgepodge of fiber:

Hodgepodge

Into the Toadstool Hat.

toadstool hat

After a bit of carding–using both the drum carder and hand cards–I came up with some shades that at least resemble the ones used in the patterns. I’ve used a real hodgepodge of fiber–shetland (some from Sal’s sheep Blackberry!), finn, a little alpaca here and there as well as some merino from the depths of my fiber stash.

Batts

Like I said, getting the shades to approximate those in the patterns will be a challenge. I’m not going to be upset if they’re not the perfect hue. Some of these will require further blending with hand cards before spinning. Hand cards are not just a color blending tool, but fabulous fiber fluffers. On a project like this spinning from fluffy rolags will be perfect.

What I am concerned about is thickness of the singles and the finished plied yarn. My yarn always tends to be a bit on the thick side. However I do have some Jamieson 2-ply to show me exactly what I’m trying to achieve. I’ve also dug out my yarn gauge.

Another resource is the Spin your own Fair Isle kit article from Knitty, which got me started on this in the first place. Lots of good advice and step-by-step instructions.

Now for the spinning.