Abstract: An optical filter is formed as a rectangular parallelepiped having a plurality of beveled edges formed thereon, preferably three non-intersecting beveled edges formed at an angle of 45 degrees. The filter is formed of a clear, transparent, durable, shock-resistant material, preferably abrasion-resistant Lucite.TM. acrylic resin (trademark of the Du Pont Corporation) impregnated with a subtractive dye. The material has a refractive index closely matching that of glass, but is tougher and more shock resistant. The filter dimensions are in the ratio of small whole integers, specifically 2:3:4, for example, 1.times.1.5.times.2 inches. The beveled edges increase the residence time of light within the filter. By positioning differently colored filters of different orientations in optical series, many different hues may be produced.