Success came quickly for Plumb. He represented in the AIA abstract exhibitions of 1953 and 1957, in Situation exhibitions 1960 -1961, alongside Bridget Riley, William Turnball, Robyn Denny and notable others. At that time Plumb was making bold, handsome, and colourful compositions, in which what appeared to be the results of rigorous discipline - chiefly hard-edged shapes of a single hue together with an immaculately crafted finish - had been produced by methods that were partly improvisational. By the mid-1960s Plumb was producing large fields of a single colour with narrow, sometimes scarcely visible, margins of other colours intended optically to modify the effect.