What aspect of visual arts does 'space' pertain to?

The aspect of visual arts that pertains to 'space' primarily refers to the area surrounding an artwork. In visual arts, space involves the notion of three-dimensionality and the relationship between objects within a given composition. It considers how elements are arranged within a work of art, creating the illusion of depth and perspective. This can encompass both the physical space that an artwork occupies and the way it interacts with the viewer's perception.

While the other choices touch on relevant concepts in art, they do not accurately capture the broad definition of space. The physical materials used relate more closely to texture and form. The reference to only the background of paintings overlooks the full scope of spatial relationships, which extend beyond just backgrounds to include foreground, middle ground, and how objects relate to each other within the entire composition. Similarly, color depth and intensity pertain to color theory and its impact within artworks but do not directly define the concept of space in visual arts. Therefore, the correct understanding of space encompasses the entirety of an artwork's environment and how it influences the viewer’s experience.