Could I ask your help please with a photo I am working on of a lady who died earlier today

[paulloseby]

I was asked by a family, if I could colourise a photo of this young lady when she was young.  I'm reasonably happy with everything but the hair.  In the BW photo, it shows black and yet the hair is a very light auburn.  I keep trying but getting nowhere.  Has anyone any suggestions please?  The last photo is of her natural hair colour that I am trying to match.  Very many thanks