This week: We go indigo vat heavy.
Each week, we are emailed with questions from our natural dye community asking simple and complex questions that we thought might be worth sharing. Here are a handful from this week answered by natural dyer in chief, Kathy Hattori, Founder of Botanical Colors:
How do you know if the indigo vat is over reduced? I think I put waaay to much fructose in mine the last time I was trying to balance it.
An over-reduced indigo vat will be very yellow with no hint of a greenish or brown tint in it. You can stir or aerate the vat with a whisk and it will acquire a slight greenish tint which indicates it is more balanced.
Should I buy ph strips for my indigo vat? Can I buy through you? I have natural dyed in the past, but this is my first time doing an indigo vat outside of college so thanks for making it a possibility!!
For me, pH strips are an indispensable tool. They immediately tell me if my vat condition requires more alkali or reducing agent. We provide handy instructions that help you read pH strips, even with indigo vats.
I have not been able to get my indigo vat to reduce. I had a great stock, put it into the vat, and have not gotten it to move past blue. I completed every single step recommended, and I still have an under reduced vat! Help! I even tried with a second vat. Same results.
If the vat is under-reduced and your pH is at the correct level, which is between 10 and 11 for cellulose, then add more reducing agent. Sometimes you need to add a lot of fructose to jump start a vat. I’ve found that using a combination of fructose and henna also works very well. The fructose dissolves very quickly and doesn’t leave a residue and the henna seems to have a much longer staying power in the vat. I’ve also had super stubborn vats that absolutely refuse to reduce, and when I walk away from them for a few hours and then come back, I find that they have quietly balanced by themselves.
I recently purchased appropriate supplies and used Michel Garcia’s 1-2-3 Indigo Vat on a relatively fine/soft Romney roving. I used a strong vat, that is 100 grams of indigo, 200 grams of pickling lime, and 300 grams of fruit sugar. The color is lovely, but the wool came out very scratchy/harsh. Is that typical? Any thoughts on how to prevent?
The calcium hydroxide can leave a residue that feels stiff. One trick is to keep your fibers out of the sediment at the bottom of the vat, and another tip is to try some hide glue in your vat to help protect the fibers.