shine

Shine is a term used to describe perceived brightness or the reflective quality of a surface or object. It can refer to light that is emitted, as from a lamp or the sun, or to light that is reflected by a material. In optics, shine often connotes a specular, mirror-like reflection, while in everyday use it also covers diffuse, even glow-like brightness from rough or painted surfaces.

The apparent shine depends on illumination, geometry, and the surface microstructure. A smooth, polished surface tends to produce a strong, directional shine called specular reflection, whereas rough or matte surfaces scatter light, producing diffuse shine. Coatings, wetness, color, and texture can enhance or diminish shine. The science of shine intersects with color science and measurement, where gloss meters assess specular reflectance at defined angles and report gloss units.

Shine is important in various fields: metalworking and ceramics rely on intentional polishing to create desirable shine; automotive finishes and consumer plastics are finished for gloss; cosmetics emphasize shine on skin or hair. In nature, polished minerals, wet surfaces, and icy or snowy scenes reflect light with high shine. In astronomy, the apparent brightness of stars and planets is described as their shine.

In culture, shine can symbolize excellence or vitality; expressions such as "let your shine through" reflect this metaphorical use. The term is related to, but distinct from, gloss (surface finish), luster (overall quality of a surface sheen), or glare (uncomfortably bright light).