I use this gradation chart for students to learn how to manipulate tone to turn shapes into form. When I started using this scale exercise several years ago, I noticed an improvement in their ability not only to identify the different degrees of light and dark values in other's art, but also how to apply it to their own. It also become a healthy challenge for them to perfect this scale. The next step is to let them draw a shape using a template and to shade it using these methods. Then they are ready to look at a still life of forms or objects and draw applying these principles. You are welcome to use and reproduce this chart to use in your classroom. Click here to download this chart. If you would like to see this chart explained, you may visit my YouTube Channel: https://youtu.be/_4lXLfjJPB4