Which combination of colours is the most convenient during day and night time?
(1) Orange and blue
(2) White and black
(3) Yellow and blue
(4) Red and green
Answer: (4) Red and green are the most convenient combination during day and night time because of very precise visibility. In modern colour theory, also known as the RGB colour model, red, green and blue are additive primary colours. Red, green and blue light combined together makes white light, and these three colours, combined in different mixtures, can produce almost any colour. This is the principle used to make the colours on computer screens and television. The sRGB number of pure red, for example, is 255, 00, 00, which means the red component is at maximum intensity, and there is no green or blue. The sRGB number for crimson is 220, 20, 60, which means that the red is slightly less intense and therefore darker, there is some green, which leans it toward orange; and there is a larger amount of blue, which makes it slightly blue-violet.
