It would definitely be an advantage to quickly record important colors while painting in changing light. One way to accomplish this is to create small pieces of correct colors to use later in a color study, or a finished painting. Today, I gave everyone a daisy and a bachelor button. These two flowers have very different greens in their stems, This is an example of a color map created in class by a student.
This is a color study (painted on a piece of mat board with a coat of gesso) of the daisies and bachelor buttons in a red Solo cup by the same student.
Here is the final tiny 4 x 4 painting after the color map and color study by the same student. This student was my sister, the very talented Kate Church. If you click on her name, you will be directed to her web page where you can enjoy her fabulous work. What a treat to have her visit and paint with us!!