Dots, small marks or speckles, were present in the paintings from student days. The raised slugs of paint in the paintings of the fifties and early sixties were carefully placed with a fine brush from paint stacked on a palette knife. The round dots were formed by dropping paint from a loaded brush held above the canvas laid on the floor of the studio. The finest speckles, usually on paper, were applied with a loaded toothbrush directed by the thumb. Complicated calculations were made and followed. Much counting was done. No mechanical device was ever used.
In Parachrome, painted in 1964, the fields of marks were interspersed with tiny motifs: a pair of red lips, the outline of a spaceman, various cog-like shapes in bright colours, a curving breast, a mysterious row of numbers which has never been identified. Hanging in the British Painting in the Sixties exhibition at Tate Britain in 2004, these small details set the painting properly into the Pop Art era but the basic style remained unaltered and progressed smoothly towards the definitive all-over paintings made by the end of the decade.