Here are some suggestions....

Play a variation of “I Spy” with students identifying bits of a color used to make a picture more realistic. I.e. The outside of an apple may be red, but the artist uses yellow, green, black and white to make it look round and alive
Students can make their own version of the “White is for…” color wheel.

White is for Blueberry can be used has a playful way to show children ways to improve the descriptions in their writing. I.e. The specificity of saying the sky is orange also tells the reader what time of day it is. Have students identify other colors the sky can be and what mood or situation usually accompanies that color.