sombras

Sombras are the regions where light is blocked by an opaque object, resulting in reduced illumination on a surface. In everyday language, sombras refer to shadows, but the phenomenon is a general feature of vision and geometry. Shadows provide cues about the shape, position, and distance of objects and are used across art, design, and science to convey depth and contrast.

Physically, a shadow forms when light from a source is occluded. With a single point-like light source, the shadow is sharply defined. With an extended or multiple light sources, the boundary becomes blurred, creating a penumbra around a central umbra. In astronomy, umbra and penumbra describe the darkest and partial-shadow regions during eclipses.

The size and location of a shadow depend on the relative distances and angles between the light source, the occluder, and the surface. Moving the light or the object changes the length and direction of the shadow; objects close to the surface cast larger, more diffuse shadows, while distant objects cast smaller, crisper ones depending on the light geometry.

In art and photography, shadows are used to model form, create mood, and control emphasis. Techniques such as shading, chiaroscuro, and silhouette work rely on shadows to suggest volume. In architecture and urban design, shadows affect daylighting and energy use.

In technology, computer graphics simulate shadows with methods such as shadow mapping and ray tracing to achieve realism. The study of shadows intersects optics, perception psychology, and cultural symbolism, where sombras can imply mystery, danger, or the unseen.