Peter Sedgley was born in London in 1930, and studied architecture and building work. As a young architect, he was tasked with the rebuilding of post-war Britain, but resigned in protest against what he perceived as attempts to simply recreate, rather than to innovate. He then served as a radar technician in the RAF and was a founding member of a design and construction cooperative, before embarking upon a career as an artist. Self-taught, he developed an early interest in colour theory, and read Goethe and Klee. He found almost instant recognition for his series of large-scale paintings, in which he sought to "establish a tonal range following the chromatic order, so that a pure colour can be equated tonally with a mutated colour". When unveiled in his first solo show at McRoberts and Tunnard, the exhibits were sold to the Tate as well as the Arts Council of Great Britain. A year later, he was included in The Responsive Eye, at the Museum of Modern Art, New York. This seminal survey show was the first to provide a comprehensive overview of such new trends in modern art, and which was soon to become known as Op Art. The paintings of Josef Albers, Frank Stella, Vasarely and his friend Bridget Riley all featured in this large-scale exhibition.
To further his investigations into colour theory and visual perception, Sedgley began a series of Target paintings. These comprised concentric circles, painted in colours against a black background using a soft-edged spray. Circles were chosen as he believed them to be a neutral shape, and so encouraging the audience to see colour, rather than shape. He realised soon after completing these paintings that light could create colour changes and a sense of apparent movement. "I observed that a cold light intensified some colours and modulated others and warm colours did the contrary". He was therefore inspired to introduce lights, which he programmed to a specific, meticulously researched colour sequence, to create a "dialogue between painted colour and illusion". Sedgley has likened the making of these works, and the ordering of the colours, to the "tuning up of a musical instrument". Known as Colour Cycles, examples were sold to the Tate Gallery in 1970, and the Arts Council of Northern Ireland in 1971. The duration of the light sequences range from a few minutes to forthy-five minutes; the sequence for the painting in the Tate's collection lasts for around ten minutes.
In 1971, Sedgley moved to Berlin, where he has remained ever since. In addition to lights, he introduced sounds to his paintings, as part of the Donaueschinger music festival in 1972, and in the following year collaborated with York Höller on Light Ballet for the Bordeaux Festival. In 1974, in Haus-am-Waldsee, he worked with the composer Mario Bertoncini, who had invented a type of wind harp. This was placed in a room and played by a performer, with light changes dictated by the frequencies of the sounds that they made. Though he removed himself from the London art scene, Sedgley was still included in a number of notable museum exhibitions at this time, including the Royal Academy's survey show of British painting from 1952-77, as well as the Tate's Silver Jubilee exhibition, both staged in 1977. He showed sporadically around Europe in the 1980s, including at the Redfern Gallery in 1983, before solo exhibitions were held in New York and Prague in the following decade. In 1997 he made Colorama, which uses solar power to move a mobile of glass and steel, for the Conference Centre in Dubai. Most recently, Sedgley has been part of museum survey shows of Kinetic and Op Art, in Paris, Lisbon and London, including Electronic Superhighway, at the Whitechapel Art Gallery in 2016.