I have compiled all the recommendations given to me for covering my stubborn gray and here is what I have surmised. I would appreciate if you would confirm if the recipe/ steps are valid. I understand that I may still have to experiment but wish to get this right. Thanks in advance for any help and comments! I very much appreciate all the help you have given me. I hope that one day I will be able to post pictures of my success.:-)
I am using Celebration Dark Brunette Kit for gray coverage.
1) Mix henna with lemon juice. Keep it in a warm place (~75 degrees F). Dye release for 8-12 hours. OR use apple juice to mix henna (less acidic) and hence may not inhibit henna dye uptake. OR Use only amla powder to mix henna. (If Amala powder is used to mix with henna, do not follow the step 2 listed below and just mix henna to indigo after indigo is prepared separately as noted below).
2) To tone down red, mix amla powder as per the directions from Amala literature posted on Henna for hair:
Do not add amla directly to indigo as the acidity of amla inhibits indigo's dye release. Make sure the amla paste is mixed separately from the indigo paste, and add each separately to the henna paste.
3) Mix indigo separately in warm distilled water. Let it sit for 10 minutes for dye release, then add the henna-amla mixture to indigo pate and mix throroughly.
Keep the mixture on hair for about 2-3 hours or less. (Timing still continues to be the gray area-no pun intended. ;-)
Here is an example of Megumi's 2-step process that was recommended to me a while ago by Carrie.
The 2-step technique means you henna first, then rinse out and apply a second step. For black, that would be 1 hour of indigo. For brown, that would be either indigo for a shorter time (15-30 minutes perhaps - to be determined by strand testing) or a mixture of henna and indigo. Having a foundation of henna in the hair already makes it easier to get complete coverage on your gray with the 2nd step.
Here is an example of one of Megumi's clients who had henna followed by 90/10 indigo/henna mixture. Each step was 90 minutes under the dryer, which would be equivalent to 3 hours without heat. So 3 hours of henna, 3 hours of hendigo. Long process ... if you had a bonnet dryer or a heat cap you could cut down the time like Megumi did.
Using a high dye content henna helps get more solid gray coverage. That's why the Dark Brunette for Gray kit contains Yemen henna, a high dye content henna. (Yemen is what Megumi was using on her clients, I believe). Celebration has even higher dye content; perhaps it would do even better on gray but we haven't had any reports yet about that particular aspect, to my knowledge.
Carrie, provided some additional input on another thread for me. I am adding it here.
Normally for a 2-step process you leave the initial henna on for at least 2 hours, but with a heat cap I think you could do 60 to 90 minutes. You need enough henna in the hair as a base to help the indigo bond well with the hair. For the hendigo step with heat you may only need 30 to 60 minutes. Megumi basically cuts the time in half when the client sits under the hairdryer.
You may find this old thread helpful - the hairdresser Megumi is advising someone about how to get good gray coverage without overly darkening her brown hair. She describes how to do a 2-step for a brown outcome on gray hair.
Nicole decided to go with a 1 step process instead: here are her results:
here is Megumi's advice for doing maintenance and roots with this mix, since there was a bit of fading on the length the first time: