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) of extremes, trying to make the colours intense, and not a harmony of greys." In the 20th and 21st centuries, the colour orange had highly varied associations, both positive and negative. The high visibility of orange made it a popular colour for certain kinds of clothing and equipment. During the Second World War, US Navy pilots in the Pacific began to wear orange inflatable life jackets, which could be spotted by search and rescue planes. After the war, these jackets became common on both civilian and naval vessels of all sizes, and on aircraft that flew over water. Orange was