Rupprecht Geiger is one of the most important German abstract artists after 1945. On the occasion of his 80th birthday, the Süddeutsche Zeitung wrote: "Geiger is one of the great completers of modernism". Geiger, who worked as an architect from 1949, was self-taught in the field of painting. He found his way to the brush during the Second World War, where he was deployed as a war painter on the Eastern Front. Inspired by experiences of nature and light, which he gathered in Greece, in the endless expanse of the Russian landscape and later in Morocco, the light takes the determining force in his later conception of art, which triumphs over the dark. Color as a carrier of light (colored light) therefore becomes an autonomous means for Geiger and is for him the most important element in painting. In the beginning he juxtaposes two contrasting colors, later he achieves an intensification in juxtaposing the non-color white with a color heightened to the highest fluorescence. The dominant colors in Geiger's artistic work were the luminous red and yellow tones. Alongside the color red - to which he devoted himself primarily from the 1950s and in which he saw perfect stimulation, energy, power, love, warmth and strength - Geiger's yellow stands symbolically for beauty and measure, strength and warmth, for light and for its creator. At the same time, Geiger is concerned with consistent reduction and clarity. He limits his palette not only to basic colors, but also to basic forms. Therefore, simple geometric shapes such as the rectangle, the square, the circular shape or the oval are characteristic for his oil paintings, watercolors and silkscreens. By detaching the color from the form, Geiger expresses its spiritual power. Geiger created numerous works in public spaces, including the facade design as a panel mosaic at Munich's main train station in 1951. His art was promoted early on by Hilla von Rebay, the founding director of the Museum for Non-Objective Painting (later the Guggenheim Foundation, New York).