I always like to start out the year with a refresher on color. It is crucial that students understand how to mix color for the rest of the year, and about 85% of my classes forget color mixing over the summer.
For ArtII I didn't want to do a basic color wheel, so I decided to incorporate a mandala lesson. The inner circle is the basic color wheel, the middle circle is color plus black, and the outer circle is color plus white. So we discussed shades and tones, as well! They only used primary colors and black and white.
I think the results turned out beautiful, but it did take a lot of individual explanations.