Change hair color from blonde to brunette

I am trying to change a model's hair color in a photo from blonde to dark brunette (need one dark brown, and one black hair).

I can change the hair color to every other color and lighten and darken it using hue/saturation, burn & sponge tool, brush with overlays, but cannot seem to successfully get a realistic brunette. At the moment all I get is a black/white effect or a deep red.

Either I am not getting the combination and settings of these effects correct or I am not using the proper photoshop tools. I can't imagine that this should be difficult.

Prhaps the photo is not bet suited to this??
(can be viewed on ht tp://

Any help or suggestions would be much appreciated!

I've never done this myself but maybe check out this tut at
Just use a brown color instead of the red?
Hair is always so tricky but possible takes time and some serious manipulating
I gave it a shot using Variations filter, with a rough selection. It worked great selection is just time consuming
jacarn: Yes, changing color is very easy, and using brown just makes for a red. Going dark and preserving a natural look is the challenge.

iDad: Ignore the selection process, as you say time consuming but I know how to do that. I tried using the variations filter but do not get something worthwhile out of it... I either get a bleached look or darker without changing the color much.. could you tell me what you did to get it to work great?