After working as an author at the beginning, Otto Ritschl took up first painterly attempts in 1918. The artist's early work is marked by abrupt changes in style. After an Expressionist phase orientated towards Oskar Kokoschka, Ritschl turned in 1920 to representations that were critical of his times and thus approached "New Objectivity". In 1925, however, Otto Ritschl also broke with this mode of expression and began to study Max Ernst and the Paris School.
From Wiesbaden, where he had been living since 1908, he went to Paris several times to stay between 1927 and 1930. Ritschl's postwar work until on into the 1950s revealed the influence of Late Cubist and Surrealist-inspired abstract symbolic forms of the 1930s. Immediately after 1945 Picasso is the dominant influence in his work until about 1954, when his forms began to consolidate. Until that point they had drawn their expressive powers from what was still a gently fluid play of flexible line. A geometric formal lexis led to more stringent organisation of composition while Otto Ritschl now eschewed painterly handling and a nuanced palette. This development places Ritschl at the opposite pole to the tachistes, who were his contemporaries and, with Leo Breuer, close to the French Constructivists, with whom Ritschl also showed his work.
The artist was represented both in 1955 and 1959 at the "documenta" in Kassel. On the death of his wife in 1958, Ritschl changed his formal emphasis. His colours liberated themselves from the stringent order he had previously imposed on them to float like islands in spacious discs against a tinted ground, becoming by 1960 independent elements of monochrome pictures for meditation. His compositions dealt from then on with the themes of being and becoming, active forces and energies, creation and meditation. The vague, blurred contours of the colour fields continued to be an essential element in the representation of such abstract ideas, both in the dynamic, cloud-like formations painted between 1963 and 1968 and the again consolidated, pulsing agglomerations of colour which dominate his late work.
On the occasion of a retrospective of his work in Munich on his 85th birthday in 1970, the artist composed "Biographical Notes".
Otto Ritschl died in Wiesbaden on 1 July 1976.