This week it is the Yellow Challenge. Yellow is like other colors in that there are warm and cool versions of it. In this painting it goes from green/yellow, a little cool, to orange/yellow, a little warm. Even though the painting is based on yellow, the warm end of the palette, the green makes it a cooler painting with a warm focal point. This is an example of the 25/75% rule.
Yellow is such a cheerful color. You can hardly make it sad. I have at least three times the number of yellows in my studio as any other color.