Name: Kay

Message: Did I read somewhere on your web page that you no longer use fiber reactive MX-8B dye?  Is this a dye that needs a 90 degree temp.?  I dyed some shirts (batiked)  in water about 70+ degrees using washing soda for fixer.  I shortened the time they are in the dye but didn`t rinse or wash them for at least 18 hours. I took the wax out in very hot water, almost boiling using soap and washing soda.  I thought I had all the excess color out.   Rinsed them and fixed them with Dharma Dye Fixative.  The color stays in for a while but loosens up after a time ( months?)  and comes out.  Is this a problem with this color.  I love the color and hate to give it up.  How is MX-5B for a color and for fastness?  Thank you for any help you can give me. 

Do you mean red MX-8B? You have to include the color base name with the code for the code to mean anything. (See "What do the letters and numbers in the code name for a Procion MX type dye mean?".)

I haven't given up using red MX-8B altogether, but I prefer to use red MX-5B in many cases. It's very close in color to the fuchsia, and works very well for mixing other colors, which is probably why one catalog's name for it is "mixing red". Its reactivity and its solubility are more similar to the other colors, so it's better to use red MX-5B when you want it to behave like the other dyes you are using it with. Red MX-8B is better when you want a maximum of difference in the behavior of your different dye chemicals, such as when you want to see turquoise halos around directly-applied purple dye mixtures. 

Red MX-8B is the most highly reactive of all of the Procion MX type dyes. It does not require a higher temperature; in fact, it should be able to handle lower temperatures than any of the other dyes in its class. For the same reasons, it tends to go bad faster, both after mixing with water, and in its shelf life while still in powder form. I do not recall noticing that either of these two red dyes washes out any more or less easily than the other.

The boiling water used for wax removal should work well for removing excess dye, too. Boiling water is the most efficient for the removal of excess unattached dye. However, there are several other factors than can make a complete washout difficult or impossible. 

One of these factors is sizing in the fabric, such as starch; when starch is used as a sizing in fabric, it canot be removed even with boiling water. Fiber reactive dyes work as well to color starch as they do to color cotton fiber. However, the colored starch will gradually wash out, resulting in the appearance of non-washfast dye, as the colored starch appears in the wash water.

Another major factor in inadequate dye washout is hard water. Dyes can form complexes with the calcium ions found in hard water, and these larger dye complexes can be much more difficult to wash out. It is important, if you have hard water, to use a phosphate-containing water softener, sodium hexametaphosphate, in both your dye mixtures and, if your water is very hard, in your washing water. You can buy this water softener from your dye supplier. Don't use a grocery-store phosphate-free water softener, such as liquid Calgon, because it contains carboxylates that interfere with dyeing.

I always recommend that dyed items be rinsed in cool water before they are washed in hot water, and I do not use soda ash when boiling out wax; instead, I use a few drops of a true soap, such as Dr. Bronner's liquid castile soap. (Don't pull your fabric out through the melted wax at the top of the pot, because some of the wax will go back into the fabric, but instead allow the wax to cool and harden before you remove the fabric, so that you can brush the wax off.) Hot water in the presence of salts and other auxiliary chemicals encourages the hydrolyzed dye to form a loose attachment to the fiber, similar to the way less washfast dyes such as direct dye cling to the fiber, which makes it more difficult to do a good washout of the unattached dye.

I think it is a mistake to use Dharma Dye Fixative, or any other cationic dye fixative, such as Retayne, on fiber reactive dyes, when a good washout can be used instead. I recommend these dye fixatives only for less washfast dyes, such as direct dyes or all-purpose dyes, or in cases when a severe water shortage makes proper washing out impossible. Once you have used a cationic dye fixative, you are no longer working with the permanent bonds that form between the fiber reactive dye and the fiber; instead, even unattached, unbonded dye will be stuck to the fabric and impossible to wash out thoroughly. The problem with this is that the unbonded dye which is stuck to the fiber with the cationic dye fixative is not as wash-resistant as properly bonded fiber reactive dye. It is better to complete the washing out of the excess unattached dye before using a cationic dye fixative, but then, once you've done this, the cationic dye fixative is not necessary. Even boiling will not break the permanent bonds between fiber reactive dyes and fiber, once auxiliary chemicals have been removed. (Another popular class of fiber reactive dye, the Remazol or vinyl sulfone dyes, can become detached from the fabric if exposed to heat in the presence of soda ash, so rinsing in cool water is even more important for those.)

So next time, to summarize, I do not recommend that you give up red MX-8B, if you like it, though I would encourage you to also try red MX-5B. I recommend that you use PFD fabric (labeled "Prepared For Dyeing"), or test non-PFD fabric first with iodine to see whether or not it has starch in it; don't use starched fabric for dyeing. Get some sodium hexametaphosphate to add to your dye mixtures, and rinse your dyed fabric with cool water before you use hot water for washing out dye or for removing wax. Avoid using Dharma Dye Fixative or similar products with fiber reactive dye, at least until you've washed out all of the excess unattached dye.

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