"Blue is the sky, water, air, depth and infinity, freedom and life. Blue is the most essential color of the universe."

In 1960, the French artist Yves Klein exhibited eight drawing boards of the same size and painted with similar groups of cyan pigments at the Milan painting exhibition. Klein Blue officially appeared in front of the world. Since then, this color has been officially named "International Klein Blue" (IKB).

Klein believes that only the simplest color can arouse the strongest spiritual sensibility. The RGB ratio of "Klein Blue" is 0:47:167, but the clear data can not reduce people's shock when facing it. Blue itself symbolizes the sky and ocean and there is no boundary. Moreover, because "Klein Blue" is too pure, it is difficult to find matching colors to enter people's vision. Therefore, its impact is particularly strong. This kind of blue is known as an ideal blue and absolute blue.