"Pigment Orange 36 is a reddish orange colour of high permanence both indoors and out. Its many good qualities make it one of the most commonly used colours in the automotive industry. It is commonly mixed with quinacridone reds to produce a range of bright reds such as fire engine red. Besides modifying the colour the Azo Orange imparts opacity, superior weather resistance, excellent flow characteristics, and lower costs for the paint. With so many desirable characteristics it gains wide acceptance in many industries such as cars, printing inks, plastics, and artists colours. It is probably the most lightfast of the monoazo pigments and its lightfastness is as good as cadmium but without the higher costs and health issues associated with cadmium usage. Vermilion (Azo) is considered to be non-toxic.
The colour name comes from an obsolete colour used by the old masters. Many people believe that it is the same as Cadmium Red but the colour was a slightly more orange red than Cadmium Red in its highest grade Chinese versions, and relatively more orange in its European manufactured versions, although generally not so orange as Vermilion (Azo). The original vermilion fell out of use soon after the introduction of Cadmium Red because it had many problems. Firstly it is a mercury compound and therefore very poisonous. It also had an unreliability issue. Generally it was absolutely permanent - the vermilion red in many old master paintings attest to that - yet if the manufacturing was not up to the highest specifications the red colour could turn black within the painting. The old masters had a reputation for making apprentices spend double and triple time grinding vermilion to get a good red that would last.
Vermilion (Azo) is used as a deep red-orange. It can be used with confidence on outdoor murals and because it is non-toxic it can be used in murals in children???s play areas. Like all oranges it mixes with blues to give a range of pleasing greys and in landscape can be used to boost the orange in ochre colours or mixed with blues and violets to find those transition colours as rocks come out of deep shadows into the light. Vermillion also has the great advantage for the artist on a budget of being more affordable than other deep orange colours.