Re: Interesting color results.
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Posted by Catherine Cartwright JOnes on July 31, 1999 at 00:41:52:
In Reply to: Interesting color results. posted by Amy C on July 21, 1999 at 06:31:46:
Why is the color changing? A chemical reaction. Henna is an acid dye, and sweat (not acid, expecially in hot weather if you're heat stressed) will make it darker. Heat makes it darker....and air makes it darker. That's oxidation if I understand it right....... The hotter we are, the more our sweat and other damp excreta tend to be closer to ammonia. Remember Jason's orange socks...a post way back? If you put your hennaed hands in ammonia, not only is the henna stain percipitated to black, but the ammonia left in the dish becomes orange-brown!!!! Jason's socks became orangey after he hennaed his feet and washed them off. His foot sweat percipitated the hennotannic acid to it's darker salt, which is what is going on. (Unless I've got it wrong, but several MD's and chemists tell me I'm right on this one. ) Just sitting out in the air makes henna go darker, heat makes henna go darker, sweat makes henna go much darker, heat stressed urine makes henna go LOTS darker (but is yukky) and household ammonia and other thinga about ph9 make henna go jet black (but may be caustic and harm your skin if you don't have a heavy callous build-up).
Now...if you're a Bedouin, you not only have a lot of heat-stressed base PH sweat dried on your skin, you have lots of 130F temperatures, you have regular access to stale camel urine, you live around high-PH lime-heavy dust, and you have wood ash on your hands from fixing dinner. Therefore....you have glorious to-die-for natural black henna with no PPD anywhere around. (on the other hand....being Bedouin is not an easy way to live, even if you're a 19th century "Bedouin Battle Virgin" which is glorious and romantic, but I wouldn't want the job. It's a bit off topic, but if you're curious, I'll post on it!) Suburban Americans have the occasional heat wave and wonder what wonderful thing just happened to their henna! They just got ethnic all of a sudden!
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