At first the children seemed to paint with the colors as they were...
Then the mixing began, carefully creating colors and asking each other which colors to mix to make other colors.
Soon all of the paints were a beautiful brownish purple.
In preschool we want children to explore the materials we put out. We don't worry about an end product because at this point in development children benefit from using the materials as they see fit. It is more important to first learn the properties of paint and enjoy how its squishy, how it moves across the page, and how the colors pop out on the plain paper.