Friday, April 25, 2008
Not All Dyes are Created Equal
Just one more picture of all the pretty trillium. With the cold wave that is coming next week, who knows whether they will be covered in snow or not.
This has been a day for two separate questions around dyes so thought I would address them in my blog which was supposed to be about dyeing anyway, not flowers!
There are basically several different kinds of dyes and even paints that are mislabelled as dyes upon occasion. The kinds of dyes that most quilters are using these days are called cold water fiber reactive dyes. They were invented not all that long ago but the patents have run out on them. There are several sub-types under that but I won't attempt to describe the differences as I claim just enough chemical knowledge to be a little dangerous. There are far better experts out there like Doug Wilson on the Dyerslist and Paula Birch who has her own website with lots of information. These cold water fiber reactive dyes work well with "cellulosic" fibers -- i.e., linen, rayon, bamboo, and cotton. They happen to also work very well on silk which has the properties of both animal and vegetable fibers with respect to these dyes. The most popular of these dyes are the Procion MX dyes which is what many of us use exclusively with cotton. On other posts, I have described some of the differences I see within that group of dyes known as MX. Even though they work the same way, each color has it's own individual properties.
A second type of dyes and one that is most popular with dyers of wool and silk (and also nylon) are the acid dyes. They require heat and an acidic medium to set the colors. This is accomplished either on the stovetop (or crockpot) or by steaming. I literally know nothing about this class of dyes as I actually use those aforementioned MX dyes to dye silk.
A third set of dyes are the direct dyes. I liken these to paints as they don't form any kind of real bond with the fibers but sit on top of the fiber (or maybe even surround it). If you see a dye that requires no heat (except for an iron) or other chemicals, I would suspect that it is a direct dye.
The popular RIT dyes are a combination of an acid dye and a direct dye. Therefore they work pretty well on silk, wool or nylon. You will get some color on the cellulosic fibers but this will wash out every time you wash the fabric, fading more each time and fading rather rapidly.
Then there is the class of dyes which people call "natural". I think this is a bit of a misnomer as the chemicals used with many of these dyes are far more deleterious than anything you would find in the other dyes! I think they are called natural as the color elements are obtained from naturally occurring plants and animals but unfortunately, for these dyes to "take", they need a mordant, alum being the safest. These dyes also do not work well on cellulosic fibers but create some beautiful colors on silks and wools.
Haven't you always wondered why people think that "natural" is better somehow? Chemicals are chemicals, whether they are natural or manmade.
Just some more spring flowers for your viewing pleasure!
Even I have taken enough pictures of trillium for this year!!