FEEDBACK FRIDAY: This Week in Natural Dye Questions

This week: iron stains, straining and repeat offenders

Every week, we are emailed with questions from our natural dye community asking simple and complex questions that we thought might be worth sharing. Of course, all of your burning questions are answered by natural dyer in chief, Kathy Hattori, Founder of Botanical Colors.

I am reaching out to you because I am having issues with my iron dye baths and I don’t understand why..! It’s driving me nuts because the same thing keeps happening and I don’t know why. I’ve been trying to dye different forms of silk and every time I use iron, I get small gray stains on my materials. I keep wasting my materials because of this and I don’t understand why this is happening or how to avoid this from happening! I hope you can help me because I’ve done online research with no answer… I use very small quantities of iron (a pinch at most!), do the bath in a plastic bin, in cold water. Anxiously waiting on your reply!

The spots can be a result of your fabric being contaminated with the way you are handling the iron in your studio, and/or not completely dissolving iron when you make your bath.

Let’s address the studio practice first.  When we work with iron in the studio, we make sure that anything that could be affected by getting a spot of iron on it is covered or put away.  This means covering up fabrics and moving them safely away, and measuring the iron with a paper towel underneath so that it catches any tiny particles of iron powder.  Then we clean the surfaces once we’ve used iron, which includes our hands, the scale, the spoon, the beaker and wipe down counters. That way we’ve cleaned up any inadvertent contamination.

The second reason staining can take place is that the iron is not completely dissolved and when you put the fabric into the iron bath, the undissolved iron settles on the fabric and causes discoloration.  Try dissolving the iron in cold water first with a teaspoon of white vinegar.  The vinegar will help the iron dissolve.  You should not see any iron particles in the water. If you do, strain the iron solution through a filter and add to the bath.  Stir well, then add your wetted out fabric.

(Post-email) Those are precautions I was definitely not aware of! I will be much more mindful in the future. I have strained my bath to take out any residues. However, this morning I still had some residue form at the bottom of the dye bath.
Do you have a suggested time to let the iron dissolve in the water or time limit before using the bath? Should I use the bath right away, or leave if standing for some time before straining it? 

If the iron hasn’t dissolved by now, it’s probably not going to dissolve fully.  It may be that it’s also reacting with the chemicals in your water and causing a precipitate. If you are able to put something in your dye pot like a rack or a colander so that the fabric stays off the bottom, that might help, but do realize that once you put the fabric in, the residue is going to start moving around, so this may not be super helpful and you could still see spotting.
If you can re-strain the bath, do that to remove as much of the undissolved material as possible. Cheesecloth or some type of straining cloth are good for capturing particles.
Good luck!