Tar is usually black, brown-black, or very dark brown, but some wood tars can show reddish, amber, or honey-brown tones when spread thinly.
Most people think of tar as black, and that is usually fair in everyday speech. In a deep container, many tars look black because they absorb light strongly. On a surface, especially in a thin coat, the colour may become more complex.
Wood tars can show warmer colours than coal-tar or heavy bituminous products. Stockholm tar is often associated with brown pine tar rather than a flat artificial black. Pine tar on timber can produce dark brown, smoky brown, or reddish brown effects, depending on the wood and the product.
Age changes colour. Fresh tar may be glossy and deep. Weathered tar can become matt, greyed, dusty, cracked, or uneven. Sunlight and rain can leach or dull some surfaces, while absorbed tar can darken timber permanently.
Colour alone cannot identify tar. Asphalt, pitch, coal tar, pine tar, bitumen, soot, black paint, and modern roof mastics can all overlap visually. The right question is colour plus source, smell, texture, and intended use.