Orange (colour) colours on a television or computer screen), orange is generated by combining high intensity red light with a lower intensity green light, with the blue light turned off entirely. Orange is a tertiary colour which is numerically halfway between gamma-compressed red and yellow, as can be seen in the . Regarding painting, blue is the complementary colour to orange. As many painters of the 19th century discovered, blue and orange reinforce each other. The painter Vincent van Gogh wrote to his brother Theo that in his paintings, he was trying to reveal "the oppositions of blue with orange, of red
Colour cast used to reduce the blueish tint caused by daylight. Blue filters reduce the orange colour caused by incandescent light. A variety of coloured filters in varying degrees of intensity are available. Kodak's amber filters, for example, vary from palest yellow ("81C") to deepest amber ("85B"). A photographer chooses which filter to use based on the quality of the ambient light. Colour temperature meters can read the temperature of the existing lighting conditions and guide the selection of the filter. Clouded sky, for example, requires a paler amber than clear blue sky. If a filter is unavailable, flash is an alternative