Blues in the Night is an iconic Appel. He made the work during his finest years, having absorbed the Cobra experiments into a mature style without ever relinquishing the freedom he had gained. The impulse towards the spontaneous, the raw and the instinctive is fully present here. From the deep blue night, a mask-like head looms, built from thick brushstrokes and aggressive contours in vivid colours. The face is half human, half skull. It looks like a dreamlike vision. The eyes are wide open, the mouth a dark blue grimace. To the left, an orange plane glows like a last remnant of light; to the right, a large red plane flares like a listening ear. Everything is in motion. The paint does not appear simply applied, but pushed, smeared, scraped and modelled. This can only be an artwork by Karel Appel.

Appel’s way of working had much in common with that of a jazz musician: improvisation within a fixed structure, spontaneity firmly held in check. The title of the painting also refers to jazz. Blues in the Night is a celebrated American jazz standard, written by Harold Arlen and Johnny Mercer for the film of the same name in 1941. The song is melancholic, steeped in longing and distrust. The famous opening line, in which a mother warns her child against an unreliable man, sets the tone at once: this is a song about disappointed love, loneliness and the restlessness of the night. Yet Appel did not illustrate a song. He translated the feeling of jazz into paint: the free outbursts, the unexpected accents, the collision of rhythm and emotion. The blue background is a dark chord against which red, orange, white and black blaze forth.

Jazz meant a great deal to Appel. Its significance grew particularly after his first visit to New York in 1957. The city opened a new world to him. It was raw, fast, loud and free. There he met not only the painters of the New York School but also jazz musicians such as Dizzy Gillespie, Sarah Vaughan, Count Basie and Miles Davis, several of whom he portrayed. From that point on, he spent much of his time in New York.

For Appel, jazz was kindred to painting, not because it happened to be modern, but because, like his art, it revolved around freedom within form. A good jazz musician improvises but does not simply play whatever comes to mind. He knows his instrument, his rhythm, and his possibilities. Appel worked in the same way. His famous remark, “I just mess around,” was often taken at face value, but it was misleading. Appel wished to create the impression of pure release, of a painter hurling paint at the canvas. In reality, he kept his spontaneity within firm boundaries, like an improvising jazz musician. He looked for a long time, mixed colours carefully, sometimes turned the canvas around, and searched until the image was right. He began spontaneously, without a fixed plan, but as he worked, he introduced ever more structure, until an expressive image emerged from apparent chaos.

In Blues in the Night, the deep blue sounds like a bass line. The orange and red passages blare like brass. The black lines supply rhythm; the white accents provide air and counterpoint. The painting has no tranquil centre; it moves, grates and pulses. The head emerging from the blue seems not only visible but audible, as though the paint has become a shout, a laugh, a lament or an improvised solo.

That is the strength of this painting. It is a nocturnal image, charged with energy and melancholy. Appel painted the blues here not merely as sorrow, but as a life force: dark and fierce at once, raw and vital, unsettling yet wholly convincing. The work demonstrates why Appel ranks among the most important post-war artists in Europe. He made paint into an event, and in this case, almost into music.