What is the primary purpose of a fixative when used on charcoal or pastel drawings?

The primary purpose of a fixative when used on charcoal or pastel drawings is indeed to prevent smudging. Charcoal and pastel are both medium that are prone to movement and smearing because they sit on the surface of the paper rather than being absorbed into it. Applying a fixative locks the particles in place, ensuring that the artwork remains intact and the details are preserved. This is particularly important for maintaining the integrity of the artwork during handling, framing, or displaying.

While enhancing colors, providing a glossy finish, or creating texture may be desirable effects in other contexts, these are not the primary roles of a fixative. The main focus is to secure the medium and maintain the artist's original vision without the risk of unintentional alterations from smudging.