Tàpies later joined the Art Informel movement as his work turned toward the abstract in the 1950s. (rukajgallery.com)
The painterly abstraction of Sam Francis is most often associated with the American Abstract Expressionist movement, but Francis also spent a great deal of time in Paris and became linked with the parallel movement of Art Informel in Europe. (artsy.net)
Beginning in the 1950s, he played a central role in the Nederlandse Informele Groep (Netherlandish Informal Group) and the Nul - groep (Nul Group)-- which were affiliated with the European Informel movement and the ZERO Group respectively. (davidzwirner.com)