"A pencil and a piece of paper are the most basic tools for creating beautiful artwork. Even if you eventually move on to a different medium, you'll find that good fundamental drawing skills are critical. Fortunately, you can learn these skills easily through a few lessons and a lot of practice." ~Cynthia Knox
Value refers to the shades of light and dark that exist in a composition. Graphite can produce every value from light gray to black, depending on the pencil choice and the amount of pressure applied. The "H" and "F" pencils lend themselves to lighter values, and the "B" pencils are capable of creating much darker values. Value scales, such as the one shown below, help us choose the right pencils and pressure to match the drawing to a reference photo.
When an object is illuminated, its form will be defined by five elements of shading visible to our eye. These elements range from full light, which is the brightest area, to the cast shadow, which is often the darkest. Once you blend these values together, the subject becomes smooth and realistic. A: Full light, referred to as the "highlight," is generally left as the white of the paper. This area is where the light shines directly on the object. B: Reflected light is the subtle area of light along the shadowed side of an object, between the core shadow and the object's edge. It is produced by the reflection from the adjacent surface or other objects in the composition. C: Halftone represents the midtone area of the object, which is a value between the highlight and the core shadow. It is usually medium-gray and represents the true color, or "local color," of the object. D: The shadow edge, or "core shadow," refers not to the object's edge but to the dark area of the object that is receding from the light source. It is the darkest value on the object itself. E: The cast shadow is cast by the object onto a nearby surface. It is often the darkest value of the composition, yet becomes slightly lighter in value as it extends away from the object.