What is the primary purpose of a manifesto in art movements?

A manifesto in art movements serves as a foundational document that articulates the beliefs, values, and goals of the artists involved in a particular movement. This primary purpose is crucial because it helps to define the group's collective vision and sets a clear direction for their artistic practices and ideologies.

Manifestos often emerge during periods of significant cultural or political change and can be seen as a response to the prevailing artistic norms of the time. They express a desire for innovation or a break from tradition, emphasizing new techniques, styles, or philosophies. By outlining the aims of the artistic group, manifestos can energize and unite members, encourage new forms of expression, and influence the broader art community.

The other options do not align with this primary purpose. Describing famous artworks, providing critiques, or comparing techniques might be part of a broader discussion about art but do not capture the fundamental role of a manifesto in defining and promoting a cohesive artistic vision.