"For many artists this is the perfect orange with a beautiful and clean pure orange hue. It has excellent covering power and is absolutely lightfast when used in acrylic. Cadmium Yellow was developed in 1817 but the orange and red versions were not developed until many decades later and were not introduced commercially until after the First World War. In order to get a pure Cadmium Red sulfur is replaced with selenium resulting in cadmium selenide. In practice reds containing cadmium have admixtures of both cadmium sulfide with cadmium selenide and the pigment we call Cadmium Orange has an even higher portion of sulfide to selenide producing this beautiful orange colour.
Cadmium Orange is well liked by artists for the richness and warmth of the colour. It is not possible to produce such a clean and bright orange colour by mixing. Even mixing Cadmium Yellow and Cadmium Red together produces an orange that is noticeably duller than the real Cadmium Orange pigment.
Orange is the complementary of blue and as a consequence the two mixed together produce a range of neutrals. Choosing particular oranges and particular blues naturally creates a wide range of neutral colours. Cadmium Orange makes particularly beautiful soft neutrals when mixed with Cerulean Blue because both are relatively light pigments in their colour range, although the darker that result from the mixture of Cadmium Orange with Ultramarine or Cobalt Blue have a wonderfully mysterious quality about them. It is fascinating that Cadmium Orange used pure and as a mixture with blue can go from the heat of a naked flame to the soft natural greys of ashes and charred wood below.