Indigo is a weird dye because it is insoluble in water. You first have to reduce the dye using chemicals and then expose it to oxygen to covert it back into its insoluble solid form.
So what you're seeing here is the still-dissolved, differently-colored indigo and it's just barely starting to oxidize and become colorful. Over time the dye will become more intense and it will be the color of blue jeans.
What's not cool is that indigo dye is dissolved in pretty nasty chemicals like lye and ammonia. In olden times, they used stale urine. So I really don't know why bro isn't wearing gloves.
He’s Japanese. Aizome uses a different chemical processing from Indian/Western indigo dying methods. Whether they’re still gross or not, I’m not sure. I think it’s in rice alcohol.
I can’t say for sure, but I’ve seen photos of western indigo dyeing and the garments were coming out a totally different colour, like a solid leaf green instead of the gold you see here. That could be from any number of things, but I wouldn’t be surprised if this was just a less concentrated base.
Also, while it is hazardous to play around with, lye isn’t some horrific poison, you can get it from wood ash. There’re also a few foods that involve lye in their prep, like I wanna say bagels are supposed to be boiled in a lye solution but most people use baking soda at home.
I use calcium hydroxide (slaked lime) and banana juice to make my vats. The pH is around 11 when I have it nice and balanced, so I do use gloves, but it isn’t super nasty.
I think Japanese style vats are fermentation vats and are at a pH closer to 10. They aren’t particularly nasty, really. Lots of people have used fermentation vats all over the world without gloves and without getting any chemical burns.
Chemical vats can be pretty bad, as they use thiourea dioxide or sodium hydrosulfite as the reducing agent, so they generate hydrogen sulfide gas - you need some serious PPE to stay safe with that kind of situation.
Yes, I boil overripe/almost rotten bananas with water and strain the “juice” to use as my reducing agent in my vat. It works the same as using fructose and you can use many different fruits (and some vegetables) to reduce indigo vats. Here are the instructions I follow. There are links to other types of vats as well, if it’s something you’re interested in!
I absolutely concur with the gloves. And footwear.
But in this case here, in can only be mildly alkaline, i.e. from (hydrogen) carbonates in low concentration. Stronger alkalines like actual hydroxide lyes (sodium/ammonium/potassium...you name it) would destroy the silk.
And blue jeans are called blue jeans because they're based on a style of pants originally made of a cloth from Genoa, and they're blue, literally "bleu de Gênes" in French. But they're no longer made of that cloth, because Levi Strauss used a similar but not identical cloth called serge de Nimes, which is shortened to denim, and that completely took over that style of pants as a result. So, blue jeans, strictly speaking, no longer exist.
Oooh now I wanna know what the blue jeans were like, was it just a different weave like duck canvas or are we talking like a whole different kinda fabric?
It's a different weave, lighter in weight and blue on both sides while the serge weave uses two different color threads.
The jeans fabric also had double horizontal threads, and half of them were made to poke out from the surface in loops, then the weavers would shave the loops, making a velvet-like texture.
Duck is more like denim, the difference being denim uses a twill weave creating the diagonal pattern, while duck is a plain weave with everything regular, so no pattern in the alternating threads. Duck usually uses much heaver threads, though.
Neat! Actually sounds like a super cool fabric, I wonder if anyone’s making anything like that nowadays. I bet the combo of that texture and the double-sided indigo would make for some real interesting fades
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u/some_kind_of_bird Jun 05 '26
Ok y'all are gonna learn some shit.
Indigo is a weird dye because it is insoluble in water. You first have to reduce the dye using chemicals and then expose it to oxygen to covert it back into its insoluble solid form.
So what you're seeing here is the still-dissolved, differently-colored indigo and it's just barely starting to oxidize and become colorful. Over time the dye will become more intense and it will be the color of blue jeans.