February 7th, Bassacs (1987) (lot 11) and July 19th, Revision of July 3rd, Bassacs (1988) (lot 10) both represent the metamorphosis of Bridget Riley’s art at the end of the 20th century, as Riley’s coloured shapes evolved from the harmonious order of stripes and curves into compositions even more dynamic, illusory and complex. Both gouaches emerged from the artist’s series of ‘Rhomboid’ paintings; works on paper that prefaced large-scale canvases spotlighted within Riley’s major retrospective at London’s Hayward Gallery earlier this year. The rhomboid presented Riley with a shape that seemingly straddled two-dimensionality and three-dimensionality, producing a feeling of motion that broke away from her static, lined compositions of the early 80s. These divergent compositions are ‘something like a coherent fabric of colour which advances and recedes in planes’, Riley notes of the series. The rhomboids ‘assume the potentiality of planes, being separated components which can hold different colours, which in turn can take up different positions in pictorial depth’ (Bridget Riley and Michael Harrison, ‘Bridget Riley in Conversation with Michael Harrison’, in Bridget Riley: Colour, Stripes, Planes and Curves, exhibition catalogue, Kettle’s Yard, Cambridge 2011, pp.12, 16). Riley utilises the rhomboid to introduce an element of depth to the canvas, a significant development in her career-long exploration of opticality.

“Riley’s respect for perception allows her to enter into dialogue with her own artistic process. Her work is very precise, like that of the Op artists with whom critics once associated her; but she never experiences total control of her vision. Nor would she wish to. The effects she seeks inhabit an illusive medium”
(RICHARD SHIFF, ‘BRIDGET RILEY: THE EDGE OF ANIMATION’, IN: EXH. CAT., LONDON, TATE BRITAIN, BRIDGET RILEY, 2003, P. 84).

Riley rose to prominence in the 1960s at the forefront of the “op art” (Optical Art) movement. Raised in Cornwall, she developed a keen sensitivity to natural phenomena: the play of light on the water, for example, or the rustle of wind in the dunes. Riley soon discovered that the combination of shapes and hues on a canvas could evoke and conjure up such enigmas of nature. This resulted in a six-decade investigation into the retinal and psychological effects of colour, observing the mercurial interaction between tones when arranged and aligned in different combinations. Beginning with black and white compositions in the 60s, Riley’s canvases soon broke out into kaleidoscopes of colours; Riley’s ‘Rhomboid’ series sees the artist at her most confident with colour. Compositions were first mapped out on paper before being transferred onto canvas, thus the present works provide vital insight into Riley’s meticulous process of colour selection. July 19th, Revision of July 3rd, 1988, Bassacs, punctuated with black and white segments, sees Riley nod back to her monochromatic origins, whilst February 7th, Bassacs sees the artist fully embrace the hues of her distinctive ‘Egyptian palette’. Across her body of work, Riley teases out the physical energies inherent in different tonalities, relishing the rhythmic push-and-pull generated through the juxtaposition of competing colours. Both of the present works on paper anticipate similar Rhomboid paintings that are housed in museum collections internationally, such as the Tate Modern in London and the Museum für Gegenwartskunst in Germany.