Re: Hennotannic acid is a dye rather than a pigment
[ Follow-ups ] [ Post Follow-up ] [ The Henna Page Discussion Forum ] [ FAQ ]
Posted by atul on March 09, 2000 at 10:45:05:
In Reply to: Hennotannic acid is a dye rather than a pigment posted by Catherine Cartwright Jones on March 02, 2000 at 20:26:54:
: Hennotannic acid is a dye rather than a pigment .... (pigment is an : insoluble colored material that you suspend in medium like varnish to : make ink) : The most certain way to get henna to stain is to add something very : sour to powdered henna leaves. Henna releases dye in an acidic : environment. Mixing lemon or lime juice into henna powder and : leaving it a few hours is a very efficient way to get dye release. In : a standard 50x microscope field, lemon juice is 5 - 8 times more : effective than water at making dye release (so its available to bind : with collagen). There is a color release process ..... the dye stains : the skin most strongly in the 12 to 48 hours after adding acid ... : then diminishes over several more days until old henna paste barely : stains skin a sad tangerine color. : Hennotannic acid seems very reactive with oxygen .... so if you try : to just take hennotannic acid from the leaves (that brownish liquid : that appears at the surface of henna left out too long) it's not very : useful. Its reactivity diminishes on contact with air ... or that's : what I think I'm seeing, with the color sequence over several days. : : If you want to see a gif of the dye molecule of henna .... email me. : Maybe you can make better sense of why exposure to air spoils the : dyeing power of henna than I can.
Follow-ups:
|