I started out early in the day with just a few colors - some blues and fuscia - to define the large shapes. Then I started to add bits of warm and cool greens and pinks as well.
All during the festival visitors would stop and chat and we would discuss technique, what kind of photo to start from, how I chose my colors, etc. I encourage people to select photos that are taken in natural light, that capture a casual moment rather than a forced smile. When you are looking thru photos trying to decide what to turn into a portrait, look for the one that says to you "Now THAT is their personality!"
So what source of information is easier to work from - the live model or the photograph? One of the obvious benefits when dealing with a child's portrait is the photograph stays still. However, when working from a live model, I tend to find a lot more color in and around the figure, as you can see here from Friday's live demonstration.
There is a lot of energy in the mark-making, and the layering of color is more "impulsive" rather than trying to match a photo. However, since I did not get to finish that evening, I will resolve the features and finalize the piece from a photograph.
In the end, I think that portrait artists need a good balance of working from the live model and photographic references. We can take the strengths of both an put them to use in our work. If I end up with a reference photo that is a little monochromatic or too dark, I can remember the colors I find in the live model.