Like anything else, you can lapse into routine when painting, especially when painting in the studio instead of from life. Our color selection can become routine and predictable. It helps me to do a series of exercises to loosen my color sense. Anytime we can paint for the sake of learning instead of trying to create a finished painting we are going to improve our painting skills. When you change your palette to shake up you color sense it reminds you that painting is not about matching color or tone or using the same color recipe for skies or fields of grass. It’s about being able to express what you see through color, using a scheme of colors to express mood or drama in a painting.
My palette is limited so when I change it I’m really switching primaries. So instead of my usual cadmium yellow, cadmium red, alizarin and ultramarine blue, I can use yellow ochre, indian red and black, that changes the mood of painting considerably. Another would be indian yellow, permanent red rose and pthalo blue, a much more vibrant almost sweet palette. A change in palette forces you to see you subject in terms of temperature atmosphere and mood instead of predictable color schemes.