Dutch critics admired his work as did French ones, who often compared him to Odilon Redon.
"[Klein] starts from a dream of colors from which the motif gradually takes shape.
[1] Klein's work was included in the 1939 exhibition and sale Onze Kunst van Heden (Our Art of Today) at the Rijksmuseum in Amsterdam.
[2] On his 80th birthday, the Van Gogh Museum in Amsterdam held a retrospective of his work.
[3] In recent years, there has been renewed interest in his paintings, leading to a spike in prices.