Known issues with vermillion or sky blue acid dyes changing color with heat?
  • I’ve been mixing vermillion and sky blue Jacquard acid dyes to get a magenta. It looks like the color I want when I dab it on a paper towel, and I have a small sample that retained that color through the setting process. After that, I had full skeins and several other samples turn to a very blue purple or blue. I finally experimented with heating up the dye by itself (no wool or acid) in a glass jar, and witnessed the color change. I tried heating up just vermillion, thinking it might be breaking down or something, but didn’t see an extreme color change after heating the same amount of time as the blend. My dye stocks are very old. I’ll be trying this with fresh ones, and accept that I may just have to change my recipes, but I was wondering if anybody’s seen anything like this.
  • There are many factors that could be contributing to your issues with your color. Age of the dye stock certainly could be one, an other could be heat, and a very common factor is the way dyes 'take' on different substrates.
    Paula Burch has a number of discussions at her site that may help you track down the specific issue.

  • I heard from another dyer who's had experience with the sky blue becoming much brighter with heating, and I'm having the same results with fresh stock. The magnitude of the change threw me off a little bit, but now I know to adjust for it. I will always wonder how my first samples managed to escape the heat.