Yves Klein Bleu - the colour and the artist

From the Tate -
In 1947, Klein began making monochrome paintings, which he associated with freedom from ideas of representation or personal expression. A decade later, he developed his trademark, patented colour, International Klein Blue (IKB). This colour, he believed, had a quality close to pure space, and he associated it with immaterial values beyond what can be seen or touched. He described it as ‘a Blue in itself, disengaged from all functional justification’. Klein made around 200 monochrome paintings using IKB. He did not give titles to these works but, after his death, his widow assigned a number to each one.

From MOMA -
Monochrome abstraction—the use of one color over an entire canvas—has been a strategy adopted by many painters wishing to challenge expectations of what an image can and should represent. Klein likened monochrome painting to an "open window to freedom." He worked with a chemist to develop his own particular brand of blue. Made from pure color pigment and a binding medium, it is called International Klein Blue. Klein adopted this hue as a means of evoking the immateriality and boundlessness of his own particular utopian vision of the world.

"Yves le monochrome," as Klein called himself, saw the monochrome painting as an "open window to freedom, as the possibility of being immersed in the immeasurable existence of color." Although he used a range of colors before concentrating on three—blue, gold, and a red he called Monopink—he is most associated with a blue he named International Klein Blue, which he arrived at by working with a chemist to develop a binding medium that could absorb pure color pigment without dimming its brilliant intensity. A student of Rosicrucianism and of Eastern religions, Klein entertained esoteric and spiritual ideas in which blue played a vital role as the color of infinity. Keenly aware that pigment is a substance of the earth, Klein also devised methods to make paintings using the other three elements—air (in the form of wind), water (in the form of rain), and fire.
Kazimir Malevich's Suprematist Composition: White on White (1918) is the major historical precedent for recent monochrome, but Klein argued that the Russian artist's primary concern had been with form—the square—rather than with color. As a result, Klein felt that "Malevich was actually standing before the infinite—I am in it."

For more about the colour IKB - see below link
http://en.wikipedia.org/wiki/International_Klein_Blue