FEEDBACK FRIDAY: This Week in Natural Dye Questions

This week: What’s the difference between our logwood extracts and how can you piece together an indigo vat in Peru without all the tools at your fingertips? (This answer is cool.)

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.

What’s the difference between the logwood and rich logwood? Any chance one crocks less?

Logwood should not crock (rub off) excessively, no matter which variety is used. It has good washfastness, but poor lightfastness, which is why it usually doesn’t crock, but it does fade. If you are seeing excessive rubbing on dyed and dried fibers, try reviewing the scour and mordant steps, as well as the dye temperature and duration. Additions to the dye bath such as calcium carbonate can also contribute to handfeel and crocking issues as the calcium solution “sits” on the surface of the dyed fiber and can contribute to rub off.

Hi I’m a fashion designer based in Lima. I work with cotton and all kinds of natural fibers. I’m learning from local artisans about natural dyeing but only a few people know how to dye with indigo because there’s little indigo here. I want to learn how to dye with indigo with an organic formula because here everybody dyes with caustic soda. I have read a lot but if you can help here in Peru I can teach too.

Thanks for emailing – it’s possible to dye with natural indigo and with local ingredients that will work to balance the indigo vat. I am not familiar with Peruvian cuisine, but if they use cal to soak the corn for making masa for tamales or tortillas, then this is a similar ingredient that can be used in place of calcium hydroxide. As well, you can make a fructose solution using leftover or rotten fruits (not citrus like lemon or limes) and using that in place of fructose. Pears, bananas and mango all work well. Mash 1 kg of the fruit and boil with 1 liter of water, then strain and use part of this solution in your indigo vat. You can add 1 liter more water, re-boil and use the pulp again. You will need to experiment to see what the best amounts are.

Another alternative instead of boiling fruit is to use iron sulfate (hierro sulfato) for the reducing agent. It works very well for cellulose (cotton) fibers, but will damage silk and wool.

I would suggest working with an artisan who is familiar with using natural indigo and caustic, and explain you want to try this method. They will know what to look for when you make the recipe. This recipe makes a lighter vat at first, but once the vat ages and ripens, it becomes darker. From my experience, this vat uses more indigo to achieve the same shades as a natural indigo vat with caustic, but it is much gentler and with patience, you will understand how to get dark shades from this type of vat.

Related links:

How-To Dye With Indigo

FEEDBACK FRIDAY: 6 Tips for Natural Dyers Dealing With Crocking Fibers

On Makers Row: 8 Frequently Asked Questions About Natural Colors & Dyes