Category Archives: immersion dyeing

iDye plus iDye Poly didn’t work on cotton pants. What is my next step?

Name: Bernie
Country or region: Vancouver, Canada
Message: Hello Paula,

I have a quick question about dying.

I have two pairs of pants, one in black and one in a light beige colour. Both are of the same style and fit, just different colours. Now that I’ve worn the black pants for about a year, they’ve faded quite a bit. I only wore the light beige ones several times. Now I want to dye both of them to black. On the tag, it says they are 98% cotton and 2% polyester (followed by another line that says 100% cotton; I don’t know, I bought these pants in Korea).

I tried iDye today. I mixed both a regular pack of iDye and a single pack of iDye Poly together (two packs together) in 1L of boiling water, dumped it into my laundry machine, followed by a cup of table salt pre-dissolved in water, and then threw in my pre-soaked pants, and washed them for 1:30. Results were not very satisfying. The pants only darkened a little bit. However, I want to point out that:

1) The water may have not been hot enough in my washer as I ran the bathtub faucet a little bit too long soaking the pants and the washer’s hot water temperature might have been affected (in which case I might try out the stove-top method)
1A) If I do the stove-top method, won’t the intense heat cause my pants to shrink or the fibers to break down?

2) I have a front-loading washer. When I poured the pre-dissolved salt and iDye solution in the machine, it went through the holes in the washer drum and I’m not sure if some it got drained or not. But when I turned on the wash and came back 30 minutes later, the pants were all covered thoroughly in a black dye (which surprised me more when post-rinse and spin that the pants barely changed).

Now, Paula, I seek your assistance. From Googling and doing some research, it seems that you are one of the more knowledgeable people on this topic on the internet and I am curious what you would recommend as my next step.

Thank you!

Hi Bernie,

The problem is a combination of choosing the correct dye for the fiber, and using the correct temperature for the dye. The dye that I recommend for your project, Procion MX dye, will work well on cotton without having to use high heat.

The iDye Poly works only on synthetic fibers and only when boiled with the clothing, at least at a simmer but preferably at a good rolling boil, for at least half an hour. iDye Poly does not work in the washing machine, because it’s not hot enough. Even when used correctly, though, it will have little effect on clothing that contains only 2% polyester. Only one thread in fifty will even take the dye at all! Polyester dye does not color cotton at all; no matter how you apply it, it will wash out of the cotton. It’s great for clothing that contains, say, 50% polyester, when combined with the plain iDye for natural fibers to dye the non-polyester portion of the fibers in the fabric. However, you are right to be concerned about shrinkage when boiling cotton or cotton-blend fabric.

Seam stitching is nearly always made of polyester, which stays the original color when dyed with cotton dye. This may be a problem for you when you successfully dye your beige pants black with cotton dye. Did the iDye Poly color the threads at the seams of the beige pants? Probably not, because you were not heating the pants in the dye on the stovetop.

Clothing that is 98% cotton is best dyed with fiber reactive dye, such as Procion MX dye. Fiber reactive dye is better than direct dye (the type that is in iDye for natural fibers), because it lasts longer in the clothing, and because it can be applied at room temperature. Direct dye requires very hot water, preferably close to boiling, though it can work in the washing machine if the water temperature is at least 140°F (60°C). If, like many people, you have your water heater set to 120°F or below, to reduce the risk of scald injuries, you are less likely to have acceptable results with direct dye, unless your washing machine itself heats the water to a much higher temperature.

Unlike direct dye, Procion dye can be set with sodium carbonate (using either washing soda or soda ash, but not baking soda), instead of heat. It will work at temperatures as low as 70°F (21°C), though warmer temperatures are better. You can use a five- or ten-gallon plastic bucket, if you’re willing to stir it for an hour, or you can use a washing machine. Top-loading washers are better than front-loaders for dyeing, but there are instructions available for dyeing with Procion MX dye in a front-loader. Dharma Trading Company provides a recipe for “Garment Dyeing With a Front Load Washing Machine”, and Jacquard Products includes instructions for a front-loading washer near the bottom of their “Procion MX Instructions” PDF page. The fact that your pants did become visibly soaked with black dye is encouraging, even though that dye did not work.

When dyeing black, always be sure to use a lot of dye. It takes more dye powder to obtain a dark black than to obtain any other color, regardless of what type of dye you are using. For each pound of dry cotton fabric that you are dyeing, you will want to use 30 grams of black Procion MX dye powder. That’s a whole ounce! Paler colors can be obtained with much smaller quantities of dye.

In Vancouver, you can buy Procion MX dye from Maiwa Handprints. They have a shop on Granville Island, and they also sell online, as do Dharma Trading Company and other good dye suppliers. Another Canadian online source of Procion MX dyes is G&S Dye in Toronto. See my page of Sources for Dyeing Supplies Around the World.

I have to mention one other possible cause of your problem. If the pants were treated with a surface finish, such as stain-resistance or an anti-wrinkle finish, even Procion dye may not work for you. There is always a risk of failure when re-dyeing commercially-made clothing that isn’t sold specifically for dyeing. It usually works out okay, but there’s a small but real chance that it won’t work at all.

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Can I use vinyl sulphone as an acid dye on silk with citric acid for immersion dyeing?

Name: Nancy
Country or region: northeastern USA
Message: Can I use vinyl sulphone as an acid dye on silk using 1 TBL citric acid when immersion dyeing in 3.5 gallons of water? Slowly heating to 185°F and holding for 60 minutes, then slowly cooling.

Yes, this looks like a recipe that should work. You might want to use more citric acid, though.

Oddly, in this recipe, a vinyl sulfone dye may act as a true fiber reactive dye on silk, unlike other types of fiber reactive dyes, which act only as acid dyes when applied at acid pHs. You might get a combination of acid-dye-type bonding and fiber-reactive-type bonding.

PRO Chemical and Dye provides a similar recipe for immersion dyeing wool with vinyl sulfone dyes, combining 2.5 gallons of water with two tablespoons (or 35 grams) of citric acid, and simmering (about 185 degrees F, or 85 degrees C) for between 30 and 60 minutes. You’re using more water and less citric acid than their recipe. Their recipes for immersion dyeing silk with these same dyes calls for a high pH, instead, with sodium carbonate or potassium carbonate instead of the acid, but, since it is a protein fiber, silk can also accept dye using recipes intended for wool. Dyeing silk at a low (acidic) pH will tend to preserve its luster and stiffness better than dyeing it at a high (basic) pH.

The difference between acting as an acid dye and acting as a fiber reactive dye lies in how the dye becomes attaches to the fiber. An acid dye is attached to a protein fiber by means of a combination of hydrogen bonding and salt linkages. A fiber reactive dye, in contrast, is attached by a true covalent chemical bond, making the dye and fiber molecules into a single molecule, firmly bound together. The advantage of the fiber reactive type of bond is that is it much more permanent, and cannot be washed out with hot water, unlike acid dyes. See “What kinds of chemical bonds attach dyes to fibers?”.

The vinyl sulfone dyes, also known as Remazol dyes after the brand name under which they were first introduced, contain a masking group of atoms in the dye molecule; this masking group prevents the dye from reacting with the dye water, thus giving the dyes a longer life when dissolved in water, and its slow removal in a hot dyebath helps wool to dye more levelly (producing a more perfectly solid color) than it would if all of the dye were immediately able to react with the wool. There are two different ways to remove the masking group: one, which works very quickly and without high heat, is to produce a high pH with a chemical such as sodium carbonate (soda ash). Surprisingly, the other is to heat the dye in the presence of a mild acid, such as citric acid. The ideal pH for the removal of the masking group is between 5 and 6, which is only mildly acid. This takes some time, but an hour should be plenty of time for it.

Typical hand-dyeing recipes for using fiber reactive dyes as acid dyes call for producing a somewhat lower pH than is required for milling acid dyes or fast acid dyes. ProChem’s recipe’s 35 grams of citric acid in 2.5 gallons of water, or 10 liters, works out to 0.35%, while your recipe of approximately 17.5 grams of citric acid in 3.5 gallons of water, or 14 liters, is 0.125%. It would be good to check the pH of this amount of citric acid in the amount of the water you are using, and keep a record of it. (See “How do you use citric acid as an auxiliary chemical for dyeing?”.)

A note on spelling, for anyone curious as to why sometimes “sulfone” appears spelled with a “ph”, and sometimes with an “f”….The main reason why we see the spelling “vinyl sulphone” is that Jacquard Products sells a brand of vinyl sulfone dyes which they name “Vinyl Sulphon”, the intentionally odd spelling, along with the capital letters, serving to distinguish it from the generic name for the vinyl sulfone dyes. The generic name is sulfone, rather than sulphone, as decreed by IUPAC, the international federation of chemists which sets standards in chemistry nomenclature; a sulfone is a chemical compound containing a sulfonyl functional group (a sulfur attached with double bonds to two oxygen atoms), in which the sulfur is also attached to two carbon atoms. The element sulfur was often spelled “sulphur” in British writings starting in the eighteenth century and continuing until 2000, when the Royal Society of Chemists in Britain agreed to standardize to the IUPAC spelling; interestingly, sulfur had been the original spelling even in British usage. The letter combination “ph” typically indicates that a word was originally sourced from Greek, but the origin of the word “sulfur” is Arabic, not Greek.

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Is it possible to reuse Procion dye vats, to reduce salt disposal?

Name: Leah
Country or region: USA
Message: I am planning on dyeing a lot of yarn (5/2, 8/2, and 10/2 warp twist cotton, in 1/2 lb hanks) a wide range of colors for weaving purposes. I’m shooting for a range of 45-60 individual shades. I’m planning on using Procion dyes, and I’m wondering if there is a way around using all the salt that would be required for 45-60 individual vats. If I am dying several shades of the same color, could I reuse the dye vat? Meaning, load the tub with water and salt, add the amount of dye needed for the color intensity I’m shooting for, add the yarn, when the dye is exhausted, remove the yarn, add dye again for a stronger intensity, add yarn, etc. Also, how would you recommend I handle adding the pH up if I do this? Any suggestions would be helpful: If I end up dumping 150ish cups of salt into my septic tank, I’ll kill it, ditto if I pour out in the garden, etc.

My first suggestion would be to use small-volume dyebaths. Dyeing with a small volume of water requires far less salt, and can even be done with no salt at all. This method of dyeing, called low water immersion dyeing, or LWI, is the easiest dye method of all, and, since it does not require salt, produces far less difficulty when it comes time for disposal. (See my page, “How to Do Low Water Immersion Dyeing“.) You can use just barely enough water to cover the material you are dyeing, and, with the smaller water volume, you do not need as much dye per pound of fiber. With such a low volume of water, salt is not required to drive the dye into the fiber to avoid wasting dye, which is its main purpose in a large-volume dyebath. In fact, the purpose of salt in LWI, when it is used at all, is to increase the complex patterning of the different colors used in one small dyebath.

However, low water immersion dying is not suitable when you want perfectly solid colors. LWI produces a mottled effect, often with a lot of color variegation. The results can be more beautiful than solid colors, but of course there are many applications which absolutely require a single solid color for each batch. For the rest of this answer, I will concentrate on high water ratio immersion dyeing for solid color dyeing, which requires twenty or twenty-five times as much water as dyeable material, by weight.

Procion dye does not exhaust on cotton the way that acid dyes exhaust on wool. After you have used a dyebath with acid dyes for wool, most of the dye will be absorbed into the wool, leaving the dyebath noticeably lighter in color. This does not happen when you are dyeing cotton. After you have used a fiber reactive dyebath, there is a lot of non-reactive hydrolyzed dye left in the water, as the result of the reaction of some of the fresh dye with the water. Depending on how long you allow for the dye reaction, and how warm your dyebath is, there will also be active dye remaining, ready to dye the next piece of yarn that gets into the dyebath.

This means that you cannot simply reuse a cotton dyebath in the way that you can reuse a wool dyebath, with relatively little effect on the color of the next dyebath. However, if reproducibility is not a high priority, with careful planning you can reuse a Procion dyebath by starting with a pale hue, then adding more dye to it to make a more intense hue that is not hurt by contamination with the first dye color, or by starting with one color and then adding increasing amounts of one or more colors to make a mixed color.

I do not recommend reusing dyebaths if your goal is to produce the exact same colors as a previous time or the next time that you dye. If your goal is only to make a great many different beautiful colors, you can reuse dyebaths, as long as you don’t find the washout of the larger amounts of unattached hydrolyzed dye that you get this way to be a problem.

After dyeing one hank of cotton and removing it to wash, some of the dye will be in the cotton, some will still be in the water but hydrolyzed so it cannot react again, and some will still be active and ready to go, to form a permanent bond to the next batch of yarn, if you use it right away. If you wait until the following day, nearly all of the dye will have hydrolyzed, by reacting with the water, so that almost none will remain to bond to the fiber in the next round of dyeing, though the hydrolyzed dye will temporarily stain the cotton. The dye reacts with the water much more quickly if the temperature of the dyebath is higher.

All or most of the hydrolyzed dye that is absorbed into the fiber can be removed by washing, since it cannot react with the cotton to form a permanent bond. The procedure is to first rinse the cotton with cool water, to remove salt, soda ash, and much of the loose dye, then to wash as many times as needed in very very hot water, to remove the rest of the unbonded dye. Synthrapol is popular among dyers for washout, and it is a good detergent for this purpose, but the real magic lies in the temperature of the wash water. Even without the chemical bonding of fiber reactive dye to fiber, the hydrolyzed dye has a tendency to associate with the fiber, by the dye property called substantivity, which is the same property that causes all-purpose dyes to attach to cotton in a far less permanent fashion than fiber reactive dyes; water at a high temperature must be used in order to decrease the substantivity of the dye, so that it will wash out. Wash water should be at least 140°F (60°C), but it works even better at nearly boiling temperatures, and it also works better if the fiber is allowed to soak in it for a while. The bond between the cotton fiber and the Procion dye is so strong that it will remain firm even if you boil the dyed yarn. It is important to remove the unattached hydrolyzed dye, because otherwise it will wash out gradually in the laundry, giving the impression of non-washfast dye, and possibly transferring the unattached dye to other pieces, especially when damp, causing unwanted dye stains. It’s a good idea to add the water softening chemical, sodium hexametaphosphate (also known as Metaphos or as Calgon T), to both your dyebath and to your wash water, to prevent hard-water minerals from forming chemical complexes with hydrolyzed dye that are particularly difficult to wash out.

After you remove the hank of yarn from the dyebath, all of the salt and soda ash will remain, except for what soaked into the yarn along with the water it was dissolved in; the concentration of both salt and soda ash will remain the same, since the volume of the dyebath will be decreased by the amount of water that the first hank of cotton takes with it when you remove it. (Squeeze the hank gently with gloved hands, or in a stainless-steel strainer with a large spoon, to remove as much of the dyebath from it as possible.) For simplicity in calculations, you could top up the dyebath with a few ounces from a fresh pre-mixed dyebath, without dye, that contains the same concentration of salt and soda ash as the first, to return the total volume to the same amount that you started with. Other than this topping up, there is no need to add more salt or soda ash when reusing a Procion dyebath. Adding more cotton to a dyebath will very slightly reduce its pH, but, since we generally use more soda ash than is strictly needed, you don’t have to worry about this at all. (Since soda ash is not a strong base like lye, we can add more than is needed without having it increase the pH hugely.)

When reusing a dyebath, you always go from a lighter color to a darker one. For example, if you want a number of different shades of blue, let’s say that you start with a 1000-gram hank of fiber (I’m choosing this weight to make the calculations simple, but just multiply each of these dye amounts by 0.227 to get the amount for 8 ounces, which is 227 grams). It is typical to double the strength of a dyebath for each increment of color intensity, when dyeing a gradation. So, for an extremely pale color, you could dye this to a 0.3% depth of shade (DOS), by using 3 grams of dye. When reusing the dyebath, you could then aim at a DOS of 0.6%, by adding 6 grams of dye (without being sure how much of the original dye remains active, which could make it darker). For the third reuse of the dyebath, you could aim for a DOS of 1.25%, by adding 12 grams of dye, then for a fourth use you could aim at a DOS of 2.5%, by adding 25 grams of dye. Finally, for a pretty dark DOS of 5%, you would add 50 grams of dye, for dyeing a 1000-gram quantity of yarn. (For dyeing eight-ounce hanks of yarn, these amounts of dye calculate out to be 0.7 grams, 1.4 grams, 2.8 grams, 5.6 grams, and 11 grams.) If you do this whole progression, you will end up with a lot of hydrolyzed dye in your used dyebath, as much as if you were preparing a single dyebath of dark black, which is sometimes used in depths of shade of up to 10%, but you will save a considerable amount of salt.

Measuring very small weights of dye, such as 0.7 grams, is tedious and requires a highly precise and expensive scale. Instead of measuring out small weights of dye, you can use stock solutions, weighing out twenty grams of dye or more, dissolving it in water, and then measure out small volumes of this. A kitchen-type scale that can reliably measure 20 grams is much less expensive than one that can reliably measure out 0.5 grams. If you make a 10% stock solution, by dissolving 20 of dye in 200 milliliters of distilled water, then measuring out 3 grams of dye is as simple as measuring 30 milliliters of the dye-water stock solution, using a plastic syringe with milliliter marks in the side (remember if necessary that 1 CC equals 1 milliliter), or a measuring pipette, or a graduated cylinder (a more accurate version of a measuring cup). Using weight in this way is the best way to measure small amounts of dye, for precision. Different batches of dye powder may be more dense and heavier per volume, or less dense and more fluffy, depending on how the manufacturing went for that particular batch, so measuring by weight, and using stock solutions for small quantities, is always the best. If you use distilled water to make your dye stock solutions, and do not let them contact any soda ash, they will stay good for weeks if refrigerated. (Place sealed dye bottles inside a closed plastic box if you temporarily use a refrigerator that is also used for foods.)

The stock solution method also makes it easier to mix dye colors. Instead of adding a certain volume of one color of stock solution, you can add half as much of each of two colors, for example turquoise plus fuchsia to make purple. To make in-between colors, it is easy to use more of one color than another; for example, you might use 20 milliliters of fuchsia plus 5 milliliters of turquoise to make a true blue. For more ideas for mixing colors, see my page, “How can I mix Procion MX dyes to get specific colors?“. Another advantage of working with stock solutions is that you don’t have to wear a respirator when measuring dye in liquid form. You should always wear a well-fitting respirator or dust mask while working with dry dye powder, to prevent allergies.

When reproducibility is not a priority, though, and if they are not preparing a large number of dyebaths, many dyers find it easier to use small measuring spoons. One teaspoon of dye equals 5 milliliters, which, depending on the dye color and dye batch, will usually contain between 2 and 5 grams of dye. Assume an average weight of 2.5 grams or dye per teaspoon, for the sake of rough conversions. Keep in mind that some colors are much more dense than others, so you can’t expect a gram of lemon yellow, say, to have as much effect in your color mixing as a gram of navy.

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