I recently posted several of the watercolor studies of sailing on my other blog, Third Time Around. All of them were done with a limited palette: Yellow Ochre or Raw Sienna, Light Red, Alizarin Crimson, Cerulean Blue, Cobalt Blue and French Ultramarine Blue. There was a slight, very slight, touch of cadmium red light in the sail in the above study. the focus has been on using the pigments for their natural color value and their tendency toward warm or cool. Focus has been on getting the values right with the least amount of color mixing possible.
The cerulean I use for the “in light” areas. The Cobalt Blue is added as the form turns from the light. The French Ultramarine is used in the out of light areas. A touch of Alizarin is used in mixtures where the form is turning from the light.
The shapes that are struck by light are warmer. As the form turns from the light it becomes cooler as it is affected less by the sun as a light source and more by the sky as a light source. The out of light areas become even more neutralized while still retaining color reflected by near surfaces.