unpigmented

Unpigmented is an adjective used to describe the absence of pigment in tissues, cells, organisms, or materials that would normally contain pigment. It may refer to colorlessness or greatly reduced coloration caused by genetic, environmental, or chemical factors. The term is descriptive rather than diagnostic and is used across biology, medicine, botany, and materials science.

In biology, unpigmented traits most often involve melanin. Albinism is a genetic condition in which little or no melanin is produced, resulting in pale skin, hair, and often light-colored or translucent eyes. Leucism refers to reduced pigmentation in some parts of the body while the eyes may retain normal coloration. In plants, unpigmented tissues lack chlorophyll and cannot photosynthesize; chlorosis, a pigment deficiency due to stress or nutrient lack, produces pale leaves, while complete absence of chlorophyll yields white or pale tissues that may be unable to survive.

In nonbiological contexts, unpigmented describes materials without added colorants, such as colorless polymers or clear coatings. In microscopy and histology, specimens may appear unpigmented when pigment granules are absent or removed by staining, which affects light absorption and image appearance.

See also: albino, hypopigmentation, leucism, chlorosis, achromia, pigment.