I've worked on this a little more today and thought I'd better upload it again before I do too much. As you can see, I've kept pretty faithful to the original photo although I did crop the image to shift Rachael to the right. I just think it has more impact like that, more interesting than dead centre.
I hope you can see that I've added in some more colours, not just to the background but to her face and neck too. The photo does show a wide range of colours in her skin but there's a danger of just 'seeing' the browns and reds. In real life, there are shades of green, blue, purple and yellow in skin too. Sooo ... I've added in Sky Blue, Caput Mortuum, Caput Mortuum Violet (Polychromos) and Limepeel and Pale Vermillion (Prismacolor) ... so far. I've left her neck deliberately unblended for now to remind myself, and show you, where I've put some of those colours.
I've used greens, Bistre and Ginger Root (what a fab colour!) on the background but also in her skin too which helps to unify all the elements in the image. There's a danger, I think, that if you use completely different colours for the background, the portrait itself can look like it's kind of stuck onto the background. Hope that makes sense. I'm using cotton buds to blend the colours together and push the pigment into the paper. I love Colourfix paper, it takes so much punishment!
I'm really enjoying this project. A way to go yet.