semitransparent

Semitransparent describes a material or medium that transmits some portion of incident light while remaining partly opaque. It lies between fully transparent and opaque, and the degree of translucency is often described by transmittance or opacity. The term is also used for colors or images that are partially see-through when layered.

In optics and materials science, semitransparency depends on composition, thickness, and wavelength. Transmittance values range from 0 to 1, and many materials transmit different wavelengths to varying extents, producing colored or tinted appearances. Common examples include tinted glass, window films, and frosted or etched surfaces that diffuse light rather than reveal details.

In digital imaging and user interfaces, semitransparency is implemented with an alpha channel or an opacity setting less than 1. During compositing, a semitransparent element blends with the background to create overlays, glow, or glass-like effects, enabling visual layering without full obscuration.

Practice and production considerations include potential color shifts, leakage of underlying features, and printing limitations. In printing, semitransparency may lead to unpredictable results due to ink interactions, so designers may compensate with color management and halftone adjustments.

See also: transparency, translucency, opacity, alpha blending.