Category Archives: direct dye

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.

(Please help support this web site. Thank you.)

-Paula