Using Indigo over henna?

[JellyBene]

Hi, I am new here and I was wondering if anyone could give me some advice on my hair. I have previously used 100% henna quite a few times, I loved the results but I miss my natural dark brown hair. I have read that a mix of henna and indigo can result in dark brown but will this work on hair that already has henna in it?

Also what brand of henna do you reccomend?

Thanks everyone!

[Pierre]

Welcome to LHC! Despite my sig, I've never used indigo :) but I do henna my hair fairly often.