this may be a little long-winded but i need to explain everything (so i apologise beforehand!)
when i was a child (before 11ish) i had very dark black hair but as i have grown older (now 19 years) my hair had turned into a rather pleasant deep brown colour - it was very multi-tonal where some strands had a little copper/reddish hint; also, the tips appeared lighter than the top/roots...now, i'm thinking this natural colour change could have been due to years of sun exposure as well as many other factors. - before this i had coloured my black hair at a young age but im guessing all of it must have grown out, especially since my roots were brown.
last December, i used a Clairol semi-permanent hair colour and kinda did like a streaky thing (bad description) - i know this wasn't the right way to do this but anyhow, the colour was VERY faint, and didn't make any difference to my hair, until i stepped out in the sun.
ok, so about 6-7 weeks ago i decided to colour my hair black using CLAIROL NICE 'N EASY NON-PERMANENT (24 WASHES) in 83 BLACK...i like to wash my hair about 5 times a week so by now i would have expected my natural hair colour to come through...but it hasn't! my hair is SO dark and im just totally annoyed with myself for colouring it
2 nights ago i decided to use CLAIROL NICE 'N EASY NON-PERMANENT (24 WASHES) in 82 DARK WARM BROWN thinking my hair would go back to a similar tone of my previously brown hair...but it hasn't!! the only difference is that now my roots appear brown in sunlight, but my hair is still SO DARK!
i was thinking of using Colour B4 - if i was to use it, would my hair go back to black like my childhood hair, or brown like more recent/matured hair?
No-one here can tell you exactly what will happen, because we can't see your hair.
I'm guessing you've had bleached highlights and the other dyes have then stained your hair, which is why it's lighter. The B4 should remove any build-up, but if your hair is stained or if it's bleached it won't really do too much, if it does anything. (I can't see how your hair would be stained by semi-permanent stuff, but IDK what you've used.)
Go to a hairdresser and explain your situation, they'll know what to do. The B4 might just make it worse, don't risk it.