Jacobus Willem (Ko) Oosterkerk. It has not been recently that Ko Oosterkerk was admired for his black and white , highly abstract etchings. Almost in a contstructivist way he builds his compositions, but always was free, where the constructivist set their limitations.
A few years ago (2016) there was an exhibition at the Kampen Museum, which showed all the qualities of his work through the years. Just have a look at all these wonderful works by searching with Google and you will be amazed how timeless these works are. I leafed through the van Abbemuseum catalogue from 1975 and noticed the quality of all his works. I can highly recommend this artist who is on the verge of becoming much more popular, but now still is very affordable.