My notes from the demo. (I hope Seth or someone will send me a photo of the finished demo because I totally forgot to take one after the stopped painting!)
1. Started with a transparent brown oxide block in sketch to decide how big he wanted to make the image and where he wanted to place it.
2. Used cad orange and white to make a generic lit area color and started sculpting in the lit area shapes. To start to warm up some area, he used cad yellow/white and permanent rose to shift the temperature slightly.
4. One important aspect of this step was that he want back to make the shadow *shapes* more precise but simplified the variation of values within the shadows. He's working with such a small brush because this portrait is tiny. The head is actually smaller than the size of his hand.
5. The first 4 steps were finished in about 20 minutes so it didn't take long before he was happy with his "drawing" and started to work some of the transitions. In many cases he just thinned the paint and let some of the grey show through because many turning edges are cooler as they move away from the light.
Before getting too far, he threw in the highest chroma areas and the highlights. For example some bright red on the upper lip, a little richness in the cheeks and nose, eventually the eyes etc. He only put these in as they were needed to establish color/value ranges to make sure everything was on track. But, the simple additions he made were added and kept that way until the end of the portrait.