R59-1 (Sichem), 1959 Lacquer paint, gauze, paper and cardboard on board, 47 x 64 cm Courtesy BorzoGallery, Amsterdam
R59-2, 1959 Lacquer paint, gauze, paper and cardboard on board, 52 x 81,5 cm Private collection
It is remarkable that Jan Schoonhoven produced both monochrome white and polychrome reliefs in 1959. Two consecutive ‘numbers’, the reliefs R59-1 and R59-2 (both 1959), are prove of Schoonhoven's lust for experimentation. And they also show that the artist was anything but rigid in his views.
From correspondence and testimonials from contemporaries we know that an exhibition by Italian artist Piero Manzoni (1933-1963) in the Netherlands had a major influence on Schoonhoven's choice for the ‘non-color’ white. That this development took place reluctantly, is evident from the first numbered reliefs from 1959. Relief R59-1 is emphatically white, and always has been. The next relief, however, R59-2, has a polychrome skin that we usually associate with Schoonhoven's reliefs from the Informal period.
Between November 1957 and January 1958, Piero Manzoni started creating the canvases dipped in porcelain clay that from 1959 onwards were given the designation Achrome, ‘colourless’ works. In the Netherlands, Hans Sonnenberg was the first gallery owner to have an eye for Manzoni’s monochrome white works. In September 1958, the Rotterdam Art Circle organized Manzoni’s first Dutch solo exhibition. Jan Schoonhoven visited the exhibition in the company of artist-friend Jan Henderikse. Schoonhoven was bowled over by the exhibition, Henderikse recalls: “It was a real blow to us to see work that was this provocative. Jan [Schoonhoven] was enormously impressed by the order in Manzoni’s work. And everything was white, of course, white as a sheet!” 
What artists such as Schoonhoven and Henderikse recognized in Manzoni was expressed most aptly by Schoonhoven. Manzoni’s Achromes demonstrated the need to “(...) dispense with the last remains of the superfluous. We’d thought that in our work, we’d achieved a completely objective method of creating, but it turned out (…) that our method was no longer feasible.”  In the course of 1959, Schoonhoven provided several existing, polychrome reliefs with a new layer of white paint. Hans Sonnenberg remembers that Schoonhoven refered to these works as ‘my Manzoni-reliefs’. 
The reliefs R59-1 and R59-2, however, still have their original appearance. They provide a glimpse into everyday artistic practice - and show us that some revolutions take place step-by-step.
Notes:  Jan Henderikse in conversation with the author, February 11, 2011.  Jan Schoonhoven in a letter to a German collector, 21 March 1971, quoted in: Antoon Melissen, Jan Schoonhoven, Rotterdam 2015, p. 55-56.  Hans Sonnenberg in conversation with the author, 23 May 2011.
Further reading: - Colin Huizing and Julia Mullié (eds.), Manzoni in Holland, exhib. cat. (Schiedam: Stedelijk Museum Schiedam), 2019. - Antoon Melissen, Jan Schoonhoven, Rotterdam 2015.