In his book of art theory Concerning the Spiritual in Art (published in 1912), Kandinsky defined three types of paintings:

(1). Impressions – A direct impression of outward nature, expressed in purely artistic form.

(2) Improvisations – A largely unconscious, spontaneous expression of inner character, the non-material nature.

(3) Compositions – An expression of a slowly formed inner feeling, which comes to utterance only after long maturing. In this, reason, consciousness, purpose, play an overwhelming part. But of the calculation nothing appears, only the feeling.