Light and Shadow Are Necessary to Create Form
The three relatively simple forms here (a squash and two apples) are all light in value. This enables shadow tones to show well. A single light source helps define the forms.
You create form in a drawing by using value to depict light and shadow. Develop value variations carefully and slowly, and only after carefully observing the tones on the subject itself. Be sure to consider the character of your subject. For example, round or soft, turning forms will have a soft, gradual value change, while sharper edges will have a crisp, abrupt value change.
It is also vital to consider the location of your light source when using value variations to model forms and create shadows. Be sure that your highlights and shadows are located consistent with the direction of the light. Also consider the differences between types of shadows. Form shadows are those dark areas on the side of an object where the light does not hit; cast shadows are those dark areas where the light has been blocked by another object.
Light and Shadow Are Necessary to Create Form
The three relatively simple forms here (a squash and two apples) are all light in value. This enables shadow tones to show well. A single light source helps define the forms.
Three Part Composition
Charcoal on bristol board
12" × 18" (30cm × 46cm)
Detail of Apple
The form shadows in the apple goes from light to dark as the light source gets further away. A similar principle applies to the cast shadows, only they get lighter the farther they get from the object.
Detail of Squash
For the squash, I use form shadows to create the effect of the ridges. Notice how the top of the ridges are lighter (where the light hits) while the bottom part of the ridge is darker. I also gradually darken the values to give more shape to the ridges.