brightening

Brightening refers to increasing the apparent brightness of an object or scene, or the luminance of an image or material. It is a perceptual quality that depends on light, reflected light, and how observers' visual systems respond. It is distinct from hue or saturation.

In optics and photography, brightening occurs through increasing illumination, longer exposure, higher sensor sensitivity, or computational processing such as gamma correction, histogram normalization, or tone mapping. In displays, brightness is controlled by backlighting and pixel luminance; over-brightening can reduce contrast and cause clipping.

In textiles and coatings, optical brightening agents are chemical compounds that absorb ultraviolet light and emit visible blue light, making whites appear brighter under ultraviolet-rich lighting. OBAs are common in laundry detergents, fabrics, papers, and some plastics.

In cosmetics and skincare, brightening denotes reducing dullness or discoloration to give skin a more luminous appearance. Ingredients claimed to brighten include vitamin C, niacinamide, licorice extract, hydroquinone, and retinoids; regulation and efficacy vary by jurisdiction, and some ingredients carry safety considerations.

In color science, brightness is a component of color that correlates with luminance; different color spaces (such as CIELAB L*) separate lightness from chromatic components. Brightening adjustments may affect perceived contrast and color balance.