The main subject of the object-like, self-referential paintings by American artist Joseph Marioni is light. The artist plays with colour transparency and translucency.By applying transparent layers of acrylic paint, he creates colour spaces which develop an interplay between colour and light.Although at first glance they appear monochrome, depending on the incidence of light and the viewer's position they slowly reveal glimpses of their multicolour structure with its individual layers of paint, a phenomenon that is particularly noticeable at the edges of the paintings.In his work, Marioni, who was a member of the Radical Painting Group of New York in the 1970s and 1980s, thoroughly investigates the parameters of painting.In 2014 he wrote that painting as an art form was in a process of drastic upheaval, talking about the shift away from narrative representation and back to the roots of painting, the process of painting itself, the act of artfully layering colours.This catalogue, published to mark the occasion of his exhibition 'Liquid Light' at the Museum Wiesbaden, presents Marioni's works dating from the years 1970 through 2018, which constitute, both conceptually and aesthetically, a considered, coherent and complete oeuvre.Published after the exhibition, Joseph Marioni: Liquid Light at Museum Wiesbaden, Germany (29 June -- 14 October 2018).English and German text.