An optically active color filter for controlling the color of light produced by a light source. The color filter includes an optically active device positioned between a linear polarizer and an adjustable position linear polarizer whose orientation can be controlled mechanically or electrically. In a preferred embodiment, the optically active device contains a liquid optically active substance such as high maltose corn syrup. The optically active color filter may be used for controlling the color of a light source such as a stage light or spotlight and in other applications requiring a device for controlling the color of a light source.