Really subtle blonde

 

My hair used to be almost white blonde with a couple of black/brown chunks thorugh it. Got fed up with routes and straw like hair so bought some brown dye.

Now what I really like about this brown is that its soo close to my natural hair colour (even 6months later I can't see roots) but its when light hits it blonde is really subtle, and gives different tones and levels and adds some excitement to a mousey brown hair.

 

Now my question is

Is this cause of the birgh blonde base colour, or can the tresemme blonde shampoo be helping this?

 

I know it's hard to explain but I don't really want to lose this soft "highlighting" It's subtle, close enough to natural but like half a shade lighter and think it compliments me a lot.