Stained

Stained is the condition of a surface or material that has acquired coloration from a stain, a liquid or pigment that penetrates or adheres to the material. Stains are typically designed to alter color rather than form a protective film and may vary in permanence, opacity, and resistance.

In woodworking, wood stains deposit pigment or dye into the wood grain to achieve a specific color while preserving the grain. They differ from paints in that they are usually transparent, allowing the texture to show. Finishing with a sealant protects the surface.

In glassmaking and art, stained glass uses colorants added to glass to create vibrant panes; later restoration can involve staining techniques to enhance color. In microscopy, staining is a routine laboratory method to increase contrast and differentiate structures; common protocols include Gram staining and hematoxylin and eosin.

In textiles and everyday life, stains can occur from dyes, food, or other substances; removal depends on the stain's nature and fabric. Stains may be permanent or only partially removable, and some materials are treated with finishes to resist staining.