What is the main function of chalk in art materials?

Chalk is primarily used in art materials for sketching and creating highlights due to its soft and malleable nature, which allows artists to easily manipulate it on various surfaces. When applied to paper or other textures, chalk can produce a range of effects, from fine lines to broad strokes, making it an excellent tool for preliminary drawings or adding subtle tonal variations.

Chalk's versatility also enables it to blend seamlessly with other media, enhancing the visual depth and dimension of artwork. Its bright colors can serve to emphasize certain parts of a piece, creating focal points and accentuating light and shadow.

In contrast, the other options present uses for materials that are distinctly different from the main function of chalk. Liquid painting typically employs water-based mediums rather than chalk, while inking and shading are better suited to ink or pencil materials, which can provide more control and precision. Calligraphy generally requires specific tools like brushes or pens designed for creating fluid and elegant letterforms, rather than the more textured application that chalk offers.