Dyeing with false indigo plants

Historically, Baptisia species have been used as the substitutes for true indigo. There are at least three types of false indigo plants growing around my area so I'd like too see if I can extract indigo dye from these wild plants. I am partly following the procedures in these two YouTube videos.

Judith's thread
link

Liziqi's video


Both of them used Poligonum tinctorium, which has a high indican level at the flowering stage.  False indigoes are perennials here and the earliest one to bloom is cream wild indigo. So I collected 1.25 lb (592g) of that and experimented away. It will be challenging given the low concentration and small amout of material Anyway, I am documenting the progress here so wish me luck.

I clipped less than 1/3 of the branches off each wild indigo plant so they will keep on growing and producing seeds. I submerged the branches in water in a black tote to let them decompose. Air temperature is only in 40s to 70s in the next few days so a black tote will make the water warmer to facilitate the fermentation.

Here I am explaining the mechanism a bit in case someone is interested.

This is a biological process in which microbes attack the plant tissues and cells, disrupting organelles and releasing soluble indican molecules from the vacuole. Indican when in contact with glucosidase in other part of the cell is then hydrolized into glucose and indoxyl. The latter is oxidized into mostly indigo and small amount of indirubin.

It will take several days to extract enough indican this way. I am on my first day but it looks quite promising, noted the bruised leaves turn dark when they are exposed to air(oxidized).

I took a small amout of leaves and used a blender to do a speedy test. With helf an hour, false indigo sample is clearly showing the dark Prussian blue color, compared to the non-indican containing legume. The insoluble indigo pigments are very fine and needs to be precipitated by adding calcioum ions. I don't have any form of limes at home so I try alum. It helps a bit, forming bigger aggregates, but those are still small enough to pass through the coffe filter.

The yield is quite satisfying just from the small scale test. I have pigments precipitated overnight ready for dyeing test.

It has been rainy and cold so I transferred the fermentating plants to a pot to bring inside. Tissues turned soft and the color changed from bright green to olive. Blue tint visible on tge foams when I whipped hard.

The pigment sediments from the small sample yesterday serve very well as ink for painting. Embedded into the filter and even resisted rinsing with water when dried. Not fast on fabric but I was still able to try some tie dyeing.

Bought a 50 lbs bag of garden lime. I will try burning for quicklime weather permitting.

Hit some roadblock last week.

The leaves fermentation went pretty well actually. After 3 days the majority of indicators had been extracted onto the solution and converted to indoxyl. Most leaves and stems were still intact but when I took a small sample and rinsed with water, the color stayed olive green and no longer turned black. Besides, when I dipped a strip of paper towel in the solution and air dried it, the color was getting darker   in the first two days and maxed out on day 3. To rule out the possibility that some indican might not be catalized, I then tried adding extra enzymes by adding puree of red clover leaves but the color didn't get any darker. All evidence showed the extraction was complete.

I strained and removed remaining plant tissues and oxidized the solution with an electronic mixer.
Next I continued to concentrate and isolate indigo by adding lime solution. The pH was about 9 tested by the litmus paper. However I saw no precipitation as seen in the videos!

I didn't want to further dilute the solution so I ordered some fabric dye remover. It took a whole week to arrive before I could run some tests on my indigo sample from alum precipitation. Strangely, when reduced and in a alkaline solution, the pigment turned from black to brown. It was now able to dye test fabric and the color was laundry fast. All properties were similar to true indigo except the black color.

I am suspecting a brown color molecule is somehow associated with indigo despite the harsh conditions of reduction, high pH and heat. I found no publication and have no idea what it could be. Anyway,  I am going to concentrate the pigments with alum and make some shibori pieces.

Took some pictures of blooming white and blue false indigo. I will come back to collect seeds later in the season if I can still find the plant among tall grasses.

Continue to purify the black dye a bit. Supernatant is dark brown but doesn't stain the test paper strip. Precipitated dye has been washed in water several time till the sup is clear. Black and white shibori would be cool too.

Thanks for this info.

Absolutely fascinating to see that you've gone through the entire process of aqueous extraction with this plant!! But--despite widespread misinformation repeated ad nauseum on the internet & some dye books, Baptisia species are not indigoferous plants and do not contain indigo precursors (hence your results). Much of this is due to persistent confusion with the native wild indigo, Indigofera caroliniana. But this wonderfully detailed account you've given here is really useful to demonstrate what happens when you carry out an aqueous extraction with Baptisia (blackish pigment, no indoxyl, no indigo).

I do hope you'll try growing a true indigo plant next year - Persicaria (formerly Polygonum) tinctoria, aka Japanese indigo, is super easy to grow & to use --fresh leaf methods are fun and instant gratification, no dye vat necessary. (And you're already familiar with the extraction process!) I grow a variety of indigo-bearing plants myself -- Persicaria, Indigofera, Isatis and a handful of weirdos -- and sell seeds every spring, so get in touch if you're interested. I also admin for an international indigo extraction group on FB: we'd love to have you post your adventure there for the edification of all

Yes, I did figure that out later false indigo pigment does not resemble true indigo. Nevertheless, it has abundant dark pigments easy to extract and have relatively large particle size that makes tie dye very easy. The pigments are  not redox sensitive ( do need disruption of cellular compartments and oxydization to bring out the color though), but pH sensitive. Not precipitated by Ca, and precipitation by Al ion is not reversible. So I extract the pigments in high pH, concentrate in low pH, resolublize in high pH again to dye cotton fabric and fix with alum. The resulting dye is wash fast.

Here I made some samples taking advantage of the different diffusion rates, and co-dyed with other plant based pigments.

Hi May,

I am just posting here to say how novel and worthwhile this research is.

I am a fiber arts teacher and with your permission, would like to introduce this method to my students. Could I email you with some questions about the details?

Thanks so much in advance.

Hi Mitch, feel free to send me a purple moosage. I have another thread experimenting with other plants here.
https://permies.com/t/265013/dyeing/Dyeing-native-plants check it out if you are interested.

I definitely hope there are more members of the Permies forum willing to dye with false indigo in the future. I'm curious how an iron or alum mordant would affect the color of the dye. Another option would be to dye with the plant in a brass or copper kettle. This plant is abundant in local prairie reserves in my area and it's widely sold at nurseries so I might try to experiment with the plant myself if I get the opportunity next year.

I have an update I'd like to share for this thread. I found a blog post from 2019 where the blogger was successful in getting a green dye from the leaves and flowers of flase indigo (Baptisia australis) when dyeing with an alum mordant. The author of this blog mentions wanting to test the plant root as well, but was never able to test this part of the plant before the blog went inactive.
https://bittenbyknittin.blogspot.com/2019/09/dye-test-with-blue-false-indigo-part-1.html

I also found another spreadsheet on different dye plants that briefly mentions false indigo. It also suggests the plant mainly yields a green dye.
https://www.theplantlady.net/resources/Natural%20Dye%20Table.pdf

What's interesting about both sources above is that they do not mention any fermentation process with ammonia. I don't know enough about the chemistry of false indigo to know if the main dye component is from indican or from baptisol. I found this other journal article from 1915 that isolates a substance that the author calls baptisol which he links with the blackening of the plant's leaves when bruised. Unfortunately, I cannot find any later literature that explains the chemistry of this substance better.
https://www.sciencedirect.com/science/article/pii/S0021925818876979

Edit: I forgot to include the chemical formula that the author of the 1915 journal article gave: On page-16 (660 of the journal), the chemical formula given is C₁₄H₆O (OCH₃) (OH)₃. I'm not very familiar with organic chemistry, but it wouldn't hurt to see if any traditional fermentation methods or other natural dyeing techniques can yield a brighter blue substance from baptisol. I will try to see if anything shows up on pubchem.