Dan Coombs responds to the exhibition Matter at APT Gallery, London, a show of artists whose works "display abstract qualities, have a strong material presence and use their own materiality as subject."

Coombs considers "materiality as subject" in relation to the paintings of Robert Ryman, noting: "What for me is powerful about Ryman's work is that he seems to be continually forcing us to look for an element that might not be present, for something that though appearing to be the point of the whole painting structure, in fact turns out, when one searches for it, to disappear."