Every possible buyer of an immaterial pictorial sensitivity zone must realize that the fact that he accepts a receipt for the price which he has paye… - Yves Klein

The essential of painting is that something, that 'ethereal glue', that intermediary product which the artist secretes with all his creative being and which he has to place, to encrust, to impregnate into the pictorial stuff of the painting.

Through all these researches into an art that would lead to immaterialisation, Werner Ruhnau [German architect] and I came together in the architecture of the air. He was hindered by the last obstacle that even a w:Mies van der Rohe [also a German architect, famous for his reflecting glass skyscrapers in the U.S.] hadn’t been able to overcome: the roof, the screen that separates us from the sky, from the blue sky. And I was hindered by the screen that the tangible blue on the canvas constitutes, which deprives man of a constant vision of the horizon.

I dash out to the banks of the river [river the 'Loup', at Cagnes, France] and find myself amongst the rushes and the reeds. I grind some pigment over all this and the wind makes their slender stalks bend and appliqués them with precision and delicacy on to my canvas, which I thus offer to quivering nature: I obtain a vegetal mark. Then it starts to rain; a fine spring rain: I expose my canvas to the rain.. ..and I have the mark of the rain! – a mark of an atmospheric event.