How to Draw Feet in Sanguine
Even though it is a fast sketch, we can pay attention to an aerial perspective. This kind of perspective describes the proximity of objects to a viewer. Those parts of an object that are closer to a viewer, should be drafted with more strength and contrast. Of course, on such a shallow object like a foot, you won't see an aerial perspective in life. Nevertheless, a professional artist uses such an approach to create an illusion of three-dimensional space in drawing. In one sketch, I combine both pencil and chalk to make well-defined lines and wide stripes of tonal values. Chalk dust can be smeared with a finger to achieve some picturesque effect. Although I'm drawing from life, the construction of a foot is the same from model to model and once you learn how to draw it skillfully, you would easily do it without a model. In fast sketches, rendering tonal values is optional. Instead of rendering light and shadow, it is better to use tones to describe geometry and construction of an object. You may accentuate with tonal values not only shaded areas, but places where one surface changes into another, or places where anatomy plays an important role in construction of a body. For example, making accents on joints would make some fast sketch more interesting and descriptive than just simply explaining the direction of light in life. Also, make sure that the contrast of parts that are closer to a viewer is greater than contrasts of other parts. This will give depth to drawing. When drawing on white paper, darker and more contrast areas would appear closer and areas with less contrast would seem further away. The opposite is true for drawings on dark paper. White marks with high contrast would look closer and darker areas further away.
