Executed in 1976, Rill is a dazzling paradigm of Bridget Riley’s seminal optic line paintings. Composing a tantalising rhythm scoring the length of the canvas, undulating tones of acidic green ebb and flow, tumbling vertically to infinity. Espousing a quintessentially Op Art aesthetic unanimous with Riley’s idiosyncratic style, Rill recalls the evocative and organic patterns found in nature. Frictions and ruptures glide and drift, building a coherent spatial order, while a shifting sensation of depth results in an ambiguous and wondrously enigmatic pictorial field. Polychromatic and instilled with a heady dynamism, the present work’s rippling and swelling creates an intoxicating visual sensation of psychedelic effect.

Initially working exclusively in black and white, Riley began implementing colour in 1967. The artist recalls ‘I had to give visual sensation more rein – my black-and-white paintings had been about states of being, states of composure and disturbance, but when I introduced colour in 1967 this began to change. Colour inevitably leads you to the world outside…I was beginning to find my way with a whole host of sensations to do with colour’ (Bridget Riley, Dialogues on Art, London, 1995, p. 70). Investigating different ways of disrupting the vertical stripe, Riley introduces an extraordinary energy into her work, pulsating and strobing lines to offer a swirling intensity. Inexorable rotation and circulation simulates the sensation of constant movement. As such Riley encourages a profound fundamental shift in the very nature of sight and seeing itself, causing the eye to glimpse extraordinary outlines and shapes seemingly concealed within the wavering lines.

With reference to the concept of perception in Riley’s work, Paul Moorhouse argues that ‘Riley’s early paintings radically reversed the traditional relationship between the work of art and the viewer… The process of looking "activates" the painting. Its formal structure is catalysed and destabilised by the viewer’s gaze. As the mind struggles to interpret the sensory information with which it is presented, it veers from one visual hypothesis to another, vainly trying to fix the image. This state of flux generates vivid perceptual experiences of movement and light, which are the defining characteristics of Riley’s early work’ (Paul Moorhouse,‘"The Ultimate Secret of Things,” Perception and sensation in Bridget Riley’s art,’ in Bridget Riley: Paintings and Drawings 1961 - 2004, exh. cat., Museum of Contemporary Art, Sydney, 2004, p. 15).

Reminiscent of a double helix, there is a mechanical and scientific element to Riley’s sustained oeuvre. Riley’s work from the mid-1970s until the end of the decade took her concern with colour interaction and its relationship with light to new levels of complexity. The vehicle for these developments was her adoption, in 1974, of the curve form as the fundamental unit of her paintings. Riley famously stated, ‘My paintings are, of course, concerned with generating visual sensations, but certainly not to the exclusion of emotion. One of my aims is that these two responses shall be experienced as one and the same.’ (Robert Kudielka, Bridget Riley: The Eye's Mind, London, 1999, p. 79).

Riley’s revolutionary practice is informed by an array of art historical sources. Encountering the Italian Futurists at the Venice Biennale in 1960, she found that their rhythmic visual language, as well as their desire to register and provoke physical sensation, resonated deeply with her own aesthetic desires. The work of Giacomo Balla in particular, with its distinctive sequential pulse, had a profound impact on the evolution of Riley’s search for ‘virtual movement’. Four years earlier, Riley had also been inspired by the Tate Modern’s exhibition Modern Art in the United States, where she had admired the work of her Abstract Expressionist contemporaries. Whilst, for example, Pollock’s chance-orientated gestural language was in many ways at odds with the calculative precision of Riley’s canvases, she was fascinated by his dispersion of focal points and his rejection of traditional perspectival laws in favour of an all-over, multi-sensory perceptual field.

Riley’s sustained inquiry into opticality and colour has resulted in her gaining global prominence continuously throughout her career. Her landmark exhibition, The Responsive Eye, at the Museum of Modern Art in New York took place in 1965, a major celebration of Op Art curated by William Seitz. In 1968 she won an International Painting Prize at the Venice Biennale, the first British contemporary painter and first woman to receive the prestigious prize. Later in her career, following a display of her artwork in the Serpentine Gallery in 1999, Tate Britain orchestrated a major Riley retrospective in 2003. Musée d’Art Moderne de la Ville, Paris, hosted their own Riley retrospective in 2008, a testimony to the calibre of her immense painting practice.

A unique visual lexicon that remains unprecedented in today’s contemporary art climate, Rill serves as a superlative colour example of Riley’s iconic body of work.