Re: Interesting color results.
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!