Orange (colour) with green, of yellow with violet ... trying to make the colours intense and not a harmony of grey". In another letter he wrote simply, "there is no orange without blue." Van Gogh, Pierre-Auguste Renoir and many other impressionist and post-impressionist painters frequently placed orange against azure or cobalt blue, to make both colours appear brighter. The actual complement of orange is azure – a colour that is one quarter of the way between blue and green on the colour spectrum. The actual complementary colour of true blue is yellow. Orange pigments are largely in the ochre or cadmium families,
Orange (colour) series, wear orange swimsuits to make them stand out. Orange astronaut suits have the highest visibility in space, or against blue sea. An aircraft's two types of "black box," or flight data recorder and cockpit voice recorder, are actually bright orange, so they can be found more easily. In some cars, connectors related to safety systems, such as the airbag, may be coloured orange. The Golden Gate Bridge at the entrance of San Francisco Bay is painted international orange to make it more visible in the fog. Next to red, it is the colour most popular for extroverts, and as