Orange (colour) philosophy of ancient China, orange was the colour of transformation. In China and India, the colour took its name not from the orange fruit, but from saffron, the finest and most expensive dye in Asia. According to Confucianism, existence was governed by the interaction of the male active principle, the "yang", and the female passive principle, the "yin". Yellow was the colour of perfection and nobility; red was the colour of happiness and power. Yellow and red were compared to light and fire, spirituality and sensuality, seemingly opposite but really complementary. Out of the interaction between the two came orange,
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