Fibersdyed with natural Indigo will turn from green to bright blue when exposed to air. The pH of the dye bath must be very precise or the oxidation will not work effectively. Link in the comments that explains the procedure.
Fibers dyed with natural Indigo will turn from green to bright blue when exposed to air. The pH of the dye bath must be very precise or the oxidation will not work properly. Link in the comments that explains the process.
[video on the subject](https://www.youtube.com/watch?v=6yhR242MnwA&t=15s)
[video on farmers who still do it the traditional way](https://www.youtube.com/watch?v=Aj5oA0YxCi0)
That’s pretty cool.
[Indigo dye ](http://www.ecotonethreads.com/?p=247)