IKB 43 was executed in 1958, the year following the now seminal Proposte Monocrome, Epoca Blu exhibition at the Galleria Apollinaire, Milan, in which Yves Klein revealed for the first time his blue monochromes. IKB 43 is both the same size and format as the original eleven canvases exhibited in the show.
Klein's monochromes were the result of a long search for pure colour, an attempt to apply pure pigment to a support, without losing its brilliance through the binding medium. "I dislike colours ground in oil. They seemed dead to me, what pleased me above all were pure pigments, in powder such as I saw them in the windows of retail paintseller. They had brightness and extraordinary lives of their own. This was essential colour. Living tangible colour matter". (in: Yves Klein, 1928-1962, A Retrospective, New York/Houston 1982, p. 22).
For Yves Klein, pure colour, and above all blue, signified "that which is most immersed in cosmic sensibility ..... Through colour I experience a feeling of complete identification with space. I am truly free ..... as soon as there are two colours in a painting, combat begins; the permanent spectacle of this batle of two colours may give the onlooker a subtle pyschological and emotional pleasure, that is nonetheless morbid from a purely human, philosophical point of view..." (Ibid., p.243)
Klein associated the colour blue with the highest form of his spirituality. His monochrome works express what Klein referred to as cosmic sensitivity. "Blue has no dimensions. It is beyond dimensions while other colours are not ..... The blood of the body of sensiblity is Blue ..... I have consecrated myself to finding the most perfect expression of Blue." Klein believed that on receiving this immaterial esssence, the viewer becomes "extradimensional in sensibility, all in all impregnated with the sensiblity of the universe". (Ibid., pp. 245-246).