What kind of light best makes a flat object look round and real, showing its curves and bumps?

The kind of light that best makes a flat object look round and real, showing its curves and bumps, is directional, oblique light with a degree of diffusion. Directional light means the light source comes from a specific point or general area, rather than being entirely ambient, which is light coming from all directions uniformly. This is crucial because it allows for the formation of distinct shadows. Shadows are fundamental to perceiving depth and form, as they indicate that light has been blocked by a raised part of an object, creating areas of less light. Without directional light and the shadows it casts, an object appears flat and two-dimensional. The light source should be positioned at an oblique angle relative to both the object and the viewer. An oblique angle means the light hits the object from the side, or from slightly above and to the side, rather than directly from the front or directly from the back. When light strikes a surface from an oblique angle, it illuminates one side of a curve or bump while casting the other side into shadow. This creates a strong contrast between bright and dark areas, which visually defines the object's relief—its raised and recessed features. For example, if light hits a small bump from the side, the surface facing the light will be bright, and a clear shadow will form on the opposite side of the bump, making its height and shape immediately apparent. Frontal light, by contrast, tends to eliminate these critical shadows, making objects appear flatter. A degree of diffusion is also optimal. Diffusion refers to the spreading out of light from its source, making it softer rather than harsh. A diffused light source, such as a large window or a light passed through a translucent material like a softbox, creates gradual transitions between light and shadow, known as gradations. These smooth, subtle changes in tone across a curved surface are essential for conveying a sense of continuous roundness and volume. While hard light, from a small, undiffused source like a bare bulb, creates very sharp, distinct shadows and bright highlights that can emphasize texture, it can also create abrupt jumps in tone that might make smooth curves look less fluid or create overly harsh contrasts. Soft, diffused light allows for a gentle falloff from light to shadow, which elegantly wraps around curves and bumps, enhancing the perception of three-dimensionality and realism. This combination of directional, oblique, and somewhat diffused light works by sculpting the object with light and shadow, allowing the viewer's brain to interpret the variations in brightness and darkness as depth and form.