What is the main function of a wall wash in lighting setups?

The main function of a wall wash in lighting setups is to evenly illuminate vertical surfaces, making option C the accurate choice. A wall wash typically involves the use of fixtures placed at a distance from a wall to cast light across its surface. This creates a uniform brightness and helps highlight the texture and colors of the wall, which can enhance the overall aesthetic of a space.

The application of wall washing can transform a flat surface, making it appear more vibrant and integrated into the surrounding environment. It serves to improve visibility and contributes to the perception of space, which is particularly important in settings like galleries, retail environments, and hospitality spaces.

In contrast, focusing light directly on subjects involves spotlighting techniques, which is not what wall washing is intended for. Creating a three-dimensional effect typically relies on shadows and highlights from dynamic lighting angles rather than the uniformity of wall washing. Enhancing ambient light generally refers to increasing the overall illumination in a room without specifying the focus on vertical surfaces, which is the primary goal of a wall wash. Therefore, illuminating the background is a more fitting description of a wall wash's function.