Chemistry of indigo for hair?

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carolh
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Chemistry of indigo for hair?

I'm curious about the chemistry of indigo for hair dyeing, vs. fabric dyeing.  I'm an indigo fabric dyer, and I've learned that indigo powder does not dissolve in water -- it needs a strong alkaline and reducing solution to make it soluable and able to react with fabric fibers.  I've been told that the indigo powder used for hair dyeing is "Vashma indigo", but I don't understand what that is, or how it works differently than the ground natural indigo I buy from a dye supplier?  Can anyone tell me where Vashma indigo comes from, how is it made, how it works?

I'm excited about trying henna/indigo on my greying hair, and I'd really like to understand the chemistry!

Thank you, Carolh

ACWN
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Re: Chemistry of indigo for hair?

"vashma" indigo is fermeted indigo - either partially or totally, I believe. I believe the indigo thats sold by mehandi is just plain indigo powder. We just mix it with warm water into a paste and either apply after a henna application or mix with dye released henna and apply right away.

Spellstone
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Re: Chemistry of indigo for hair?

Hi,

The indigo dye is held in the plant material in a soluble biological form (yellow). Once you add water the dye passes into the solute and starts to turn blue. Once it is blue it is chemically inert and will not do a great deal to you hair - the trick is to get the as much solute into your hair before you see a colour change and have the chemistry happen on the hair shaft.

Textile indigo vats hold the dye in an alkali solution so the indigo can be re-used. In the situation above all the excess dye is discarded and not re-used. It's exactly the same as using fresh indigo leaf and bashing it up on a bit of cotton that will give you a blue stain too without need for a reducing agent.

Alex

carolh
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Re: Chemistry of indigo for hair?

Thanks.  I just got my indigo-for-hair samples and I think this is starting to make more sense to me.  The indigo I buy for dyeing is the fully oxidized and blue form of indigo.  The indigo-for-hair is pale green, it appears to be the unoxidized form of indigo.  So it makes sense that it will dissolve in H2O and then quickly proceed to oxidize to blue. 

I'm still curious to know where this form of indigo comes from/how it's made?  Is the green indigo powder pulled out of the indigo process before they oxidize the mashed leaves to make the blue indigo?  Or is it created chemically later? 

Spellstone
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Re: Chemistry of indigo for hair?

I haven't got exact info on how the leaf is processed but Vashma is a leaf product with no chemical intervention. I would expect the leaf to be harvested and kept probably kept in a moist/humid environment. Under conditions like that you'll get a little fermentation which will aid in breaking the structure of the leaf down. Next the mulch would need to be dried then ground to a powder and that's what you have in your indigo pack.

A

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