FEEDBACK FRIDAY: This Week in Natural Dye Questions

This week: Why you can’t get a deep blue and color shifting madder to be more red

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 have purchased your indigo powder, calcium hydroxide and fructose sugar to make a natural indigo vat.
I have tried 3-4 times but some reason my vat is really light. I even dip 10 times but some reason I can not get the dark color indigo.
I have tried, 1 tsp indigo, 2 tsp lime, 3 tsp fructose and follow the directions on your site.
I used a 5 gallon bucket for the 1st time.
2nd time, I made another mother and added to the first vat, and added 5 more gallon water.
3rd time, I made another mother and simply added to 2nd time vat. Still the color is not dark enough. Am I using too little content of indigo, lime and sugar??

It sounds as if you are using a very small amount of indigo in a very large container. 1 teaspoon is approximately 3-5 grams, which is sufficient to dye 1 ounce (30 grams) of fiber a medium dark shade. However, the sheer volume of the container (a 5-gallon bucket) is diluting the dye power of the indigo. Through experience, I’ve found that adding between 50 and 100 grams of indigo into a container the size of a 5 gallon bucket makes a medium to dark vat, and makes it easier to achieve darker shades. In order to create a vat with more indigo, build the mother in a larger container as the calcium hydroxide and fructose are too voluminous to fit into a quart mason jar.

I have been using your ground madder root for awhile and decided to visit your website and use your madder root tutorial for the first time. I’ve been using various notes I’ve accumulated along the way and I am a big fan of a The Modern Natural Dyer, I have found her recipes and process are in line with my previous teachers, i.e. Michel Garcia + Elin Noble. Anyhow, as I was reading your instructions I was surprised to find it said: add the calcium carbonate to the madder root vat to shift the color. I have always used it after I mordant, then I thoroughly rinse off the chalk and proceed with dyeing. I am going to experiment today and use your approach and see what happens. It would save me a step because only adding 5% of calcium carbonate to the vat would be a lot easier, than what I have done in the past. I am writing to make sure I am understand your directions clearly: you suggest adding it to the vat once you’ve reached 180 degrees and then hold it at that temperature for 30 – 60 minutes. Or do you recommend adding it with the fiber when the vat is still cool? Does it matter; (no pun intended;)

The use of calcium carbonate helps develop red in madder, especially in areas where the water is calcium poor. The water here in the Pacific NW is very soft (acidic), so when used alone, our madder root yields orange and it is with the addition of calcium carbonate that we achieve red.

It is possible to mordant with aluminum acetate, post bath with calcium carbonate, and then dye with madder root without adding any more calcium. You would probably get good color development. But I believe the calcium carbonate is being used for two different purposes here. With aluminum acetate, it’s helping change it, which helps color adhere better to cellulose fibers. I am not a chemist so I don’t know the exact reaction. Combined with the madder root, it’s helping develop the red color in the dye. So I think you can probably mordant and post bath and not add calcium carbonate to the madder bath, but I don’t really know about aluminum acetate alone, then add calcium carbonate to the madder bath as it will not have done its work on the aluminum acetate mordanted fibers. I hope this makes sense.

Regarding the instructions: I start with cool or slightly warm dye baths, have all additives and dye in the bath and well stirred, add the fiber, then raise the temperature as noted. It makes a huge quality difference to start cold and gradually work to temperature than it does to plunge fibers into hot dye pots.  Starting cold and gradually working your way up helps keep the colors even.

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