indigo sticking to hair that wasn't dyed?

 I will try the oil tip if I decide to go back to using a little indigo in the recipe.  I don't like how unpredictable that dye is on my hair, though.  I'm careful to blend it well with my (dye released) henna... I've even used a blender... in small amounts at a time, so I can apply it before the indigo demises, but I still get a patchy result.   

So for now I'm sticking with just the Twilight henna, which I mix with just 20% cassia and some fairly strong melissa balm (lemon tea) water... it's pH neutral, but I add a bit of aloe vera juice to it, which makes it pH 4-5 (tested it), dpeending how much I add.   I used to use amla instead of tea, but I noticed no color difference between the two--- amla doesn't seem to have a browning effect for me.  So maybe I will try blueberry juice. 

I hear you about the AC Vinegar, I am sure that might work to make it go browner since it's so acidic.  But for me that's a real slippery slope, because my hair is past my shoulders now and I'm wanting to grow it long... and what I'm noticing that those previously hennaned lengths and ends just keep getting darker.  Even though I do only root touch ups. 

I have tried using clarifying shampoos and rain wash on the ends, and finally even tried natural lightening methods followed by a henna gloss, to try to restore them to copper...  that helped only some--  they are just determined to be a browny-y auburn.   I think maybe that's partly because when I did my initial henna application, I used an acidic mix (amla) -- I have heard that often makes the "browning effect" just keep getting browner over time, is that correct?  Personally I'd rather have my henna fade over time and then just re-apply it, rather than have the ends just keep getting darker.  I do not use any heat tools on my hair, so I know that's not the problem.

The "reverse ombre" look (the older, more oxidized hair on the bottom being darker than the newly hennaed hair on the top) is not as bad as it sounds... the ombre effect is gradual, so it's wearable... but I am trying to minimize it over time, that's why I swicthed to a recipe that's only very mildly acidic. 

So is indigo the only way to make a orangey (on gray) henna/cassia mix go slightly more copper/brown, without using amla, vinegar, or some other acidic ingredient?  Guess I'm looking for a way to make my henna recipe slightly more copper (browner), on my brown/gray  roots,  without having it go darker and darker over time, as it grows out.  Is there a way to do that? 

Someone suggested I try Nightfall Rose, but the word "rose" really scares me off, because I have (and want) a very warm/coppery/natural shade of red right now, the cooler cherry/rosey/burgundy reds do not work with my skin tone.    

Thanks,

Maya