Photo study, mid to high chroma skin tone

The photo of the painting isn't too good, lost a lot of the subtle modelling of the face, and edges.

This is the result of a colour experiment with a painter friend, we were trying to hit the highest chroma with burnt sienna and yellow ochre (it hits the limit pretty fast, especially after adding white). I didn't take a picture of the first layer, but I approached the problem by applying a thin rubbing of the YR mixture on a white canvas- this increases the chroma dramatically. However, I don't like painting thinly. So after the first layer is dried, I mixed up a 5YR range which is about chroma 12-14. From darkest to lightest, burnt umber, burnt sienna, cadmium red light, cadmium orange, cadmium yellow medium, then white. This gives the range as you can see in the second picture.

I scumbled the middle tone over the entire head, then painted the variations "into the soup", an old school academic technique. The most challenging thing is the profile meeting the dark background- I tried applying a buffer zone of alizarin crimson. I'm trying to streamline my painting process, and the daily fundamentals are helping lots.