Colour palettes in watercolour for skin tones can be an interesting thing. Just the thought of seeing the colours even with the knowledge of colour theory individually compared to when they are applied to your canvas make it sometimes unbelievable that such skin tones are achievable.
It also gave me the idea to keep a log of successful skin tone mixtures like this one in a palette reference book for future portraits. I thoroughly enjoyed this piece. For one, I found the entire process went much more quickly than previous portraits. Additionally, my intuition to get the desired skin tone somehow seemed more responsive to picking the right ones. My Facebook has some video of the process where I laid the undertones of the complexion to the final result and it was pretty enjoyable to film. This one took me no more than 6 hours.
Do you keep a reference sheet for your swatches for different skin tones?