Blue

Blue is one of the three primar colors of pigments in painting and traditional color theory, as well as in the RGB color model. It lies between purple and green on the spectrum of visible light.

Blue has been an important colour in art and decoration since ancient times. The semi-precious stone lapis lazuli was used in ancient Egypt for jewellery and ornament and later, in the Renaissance, to make the pigment ulramarine, the most expensive of all pigments.

International Klein Blue (IKB) is a shade of deep blue close to ultramarine blue. It was first mixed by the French artist Yves Klein.

Back at the times when IKB was invented, it was a color that only its creator Yves Klein was able to produce, since then, due to its complex and unique composition, its creator decided to put a copyright on it.