Bridget Riley has devoted her career to exploring the optical and phenomenological effects of colour. Through geometric patterns and graphic sequences, she teases out the physical energies inherent to different pigments, relishing the vibrations produced by the juxtapositions of hues; Composition 1965 reveals her methodical investigations. Distinct ribbons of black, grey and white seem to quiver across the paper, hinting at a depth unavailable in paper. In her paintings from the 1960s, Riley predominantly used black, white and grey to exploit their retinal potential: ‘I found that black and white along with shades of grey, behaved in the same way colours do; that is, they interacted and developed qualities such as contrast and radiance. There are myriads of senses and if one wishes to pass through them, then he must take the road of only one of them’ (B. Riley quoted U Allemandi (ed.) Metamorphosis: British Art of the Sixties, exh cat, Calouste Gulbenkian Foundation, Lisbon, 2005, p. 85). The year she sketched Composition 1965, a selection of Riley’s black and white paintings was included in the landmark exhibition The Responsive Eye at the Museum of Modern Art in New York. Cast within a new art movement known as Op Art, Riley and her contemporaries were celebrated by curator William Seitz for creating an art that ‘exist[s] less as objects than as generators of perceptual responses’ (W. Seitz quoted in J. Borgzinner, 'Op Art: Pictures That Attack the Eye', Time, 23 October 1964).