Mid-Week FEEDBACK: Indigo Iron Vat & Expired Dyes

This week: How to make an indigo iron vat, can dyes expire and washfastness

Every week, we are emailed with questions from our natural dye community that are worth sharing. Of course, all of your burning questions are answered by natural dyer in chief, Kathy Hattori, Founder of Botanical Colors. This week we look at substitutes for aluminum acetate and using recyclables for natural dye seed cups.

What is the best process at the end of the dyeing process to ensure the washfastness of the natural dyes on clothing ? (cellulose and protein fibers )

Light and washfastness is a result of proper preparation of the fibers and dyeing. At the end of the process, you are washing out excess dyestuff from the fabrics. We normally rinse in cool water until the rinse water is clear.  You may also hand wash with gentle laundry soap.

I have an indigo eco-vat (formula 1-2-3 by Michel Garcia) and I’m revitalizing it; it has the flower in the middle of the vat; PH 10, but it’s still quite muddy. What should I do? More heating, more stirring?

If the vat is murky, it needs more time to settle. We found that one of our indigo vats took 2 days to finally clear, so it’s possible that you may need to wait a little longer.

I have been building up my little dye-lab in the past two years. Every time I feel like I can add to it, I purchase what I think I will use most, but then my life turns upside down.
Now I have a lot of dyes and mordants and not sure about shelf-life.
Before I embark on (ingers crossed) this much desired maker life in the next month or so, I was wondering if some of them might have “expired.”

The general rule of thumb for storing dye powders and supplies is to keep them away from excessive heat and exposure to light in tightly covered packaging. Henna has the shortest shelf life due to oxidation but we’ve kept it for a couple of years and it still works. PH papers need to be kept away from excess moisture so that they still work. If everything is kept dry and stored in a cool place, they should be fine. The shelf life for most of the powders is quite long. I have been using a container of cutch that I purchased in 1990 with no problems.

Sometimes the dyes attract moisture and become very lumpy, even pasty. If that’s the case, try to estimate what the dry weight of the product was and then divide the dye up estimating the “weight” and then dissolve as normal. It will not be exact but it helps salvage the dyestuff, especially expensive dyes.

I watched the video from a recent FEEDBACK FRIDAY about creating a ferrous indigo vat, using the “shake-alotta” method and using iron as the reducing agent. Though I wasn’t able to attend live, it was a wonderful video to watch, thank you so much for making it available on the blog!
My question is about the proportions in a ferrous vat:
Would you recommend substituting the iron directly into the recipe in place of the fructose in Michel Garcia’s 1-2-3 method? In other words, do you recommend 1 part indigo, 2 parts lime, 3 parts iron? Or are the proportions, when using iron, different?

The proportions are a little different:

It’s 1 part indigo, 2 parts iron (ferrous sulfate) and 3 parts calcium hydroxide. The shake-alotta method is to put everything into one jar, tighten the lid and shake like crazy to combine. Then, boil the water (it needs super hot water) and put the water into a bucket – fill about halfway – then carefully dump in the mixed powder. Wear a dust mask. Stir well, and then top off with more hot water. Let this mix rest several hours or overnight so it’s cool enough to use.
Ferrous vats are best for cellulose fibers. It’s very harsh for silk and wool fibers, but sometimes a quick dip is okay with animal fibers.

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