Fiber Reactive vs Acid Dyes
I have always used acid dyes for wool and silk because the results are good, the colors are strong and the dye is fairly light and wash fast. Since I need to use fiber reactive dyes for my stitch class, I decided to see if fiber reactive dyes (Procion MX) would work on wool.
In class, while we were dyeing cotton threads, I decided to try some wool thread. With fiber reactive dye, you use soda ash as a fixative. So that’s what I used on the wool thread. The results were very disappointing. The colors didn’t hold at all and the resultant thread was not the color expected at all especially with blue dye.
Ann then suggested that I try using an acid as the fixative with the fiber reactive dyes. So my next trial was wool thread soaked in vinegar water and then dyed. These results were much better. Still not as strong as the acid dyes but the colors held much better, even the blue.
I discussed my findings with Gail Harker (my stitch class instructor) and she questioned whether these results would be light and wash fast. So more experiments to try. I decided to take the thread I had already dyed and put it outside in the sun and rain for a month and see what happened. The photo above shows the results. The threads on the left are the control threads which I did not put outside. The threads on the right were exposed to rain, weather and sunlight for one month. I just attached them to a card and stapled them to my picnic table outside which is in full sun all day.
The top three threads are wool dyed with Procion Mx and vinegar. The second set of three are wool dyed with acid dyes and vinegar. The third set of threads (only two) were wool dyed with Procion MX and soda ash. The last set of threads is cotton dyed with Procion MX and soda ash.
I’m not sure you can see this in the photo but the wool threads dyed with Procion and vinegar faded a moderate amount. The acid dyed wool held very well and had little fading. The wool dyed with Procion and soda ash faded significantly from the color that was already really off from the original dye color. The cotton threads faded slightly.
I also sent an e-mail to the good people at Dharma Trading to see if they had some input about the use of fiber reactive dyes with wool. I learned a lot from Sharon’s (Dharma) response. She said that fiber reactive dyes were originally developed to dye wool fabric in the 1950’s. The manufacturers were disappointed with the results but accidentally discovered how well they dyed plant fibers and happily marketed the fiber reactive dyes for that use.
Sharon also said that the blue fiber reactive dyes do not strike well on wool or silk and tends to come out half strength or less. Therefore, any mixtures with blue dye will have a shift in color for example, purple may come out magenta and black shifts to brown or maroon. Blue is also the slowest dye to strike on cotton or other plant based fibers.
Sharon recommended to treat the fiber reactive dyes just like acid dyes when dying wool Therefore, use acid as your fixative such as vinegar or acetic acid and steam the fiber for 30 minutes to help fix the dyes. She also states that rinsing with higher temperature water will rinse more of the dye out so you will always need to wash/rinse the dyed wool with cool water or dry clean it. She also reports that the fiber reactive dyes will not exhaust like the acid dyes so there will be more fiber reactive dye rinsed out at the end of the dyeing process than with acid dyes.
My next experiment will be with fiber reactive dyes, acid and heat. I’ll see if that helps set the dyes in the wool better than just the acid. The nice thing about fiber reactive dyes is that you don’t have to set the dye with heat in plant fibers. But if I only had to have one type of dye, that would be better so I’ll let you know the results the next time I dye.
I’d love to hear about any experiments you’ve done using fiber reactive dyes and wool and see photos of your results. Feel free to post them on Flickr or join us on the forum and start a discussion about dyeing results.