In 1965, expatriate Aotearoa New Zealand artist Billy Apple staged his groundbreaking exhibition Rainbows at New York’s Bianchini Gallery. It’s credited as being one of the first shows to treat electric light as a sculptural medium. Taking the rainbow as a leitmotif, it demonstrated Apple’s attraction to new technology and his fascination with the science of colour and light.

In May this year, London’s Mayor Gallery restaged the exhibition as Billy Apple®: Rainbows 1965. Apple died last year, but the Gallery worked with his wife Mary to prepare the surviving works. The show included four of his seven original neon sculptures as well as three plexiglass sculptures and some screen prints. It’s the largest gathering of his rainbow works since their New York debut.

Apple became interested in neon back in the late 1950s, while working in advertising in Aotearoa New Zealand. While studying at the Royal College of Art, London, from 1959 to 1962, he drew on the skills of neon glass benders, and later used the London firm Brilliant Signs to make neon works. In 1964, he moved to New York, where none of the pop artists were working with neon. He took the rainbow as a pop icon and electrified it.

Art critic Robert Pincus-Witten, writing in Artforum, described Apple’s rainbow works as ‘among the most beautiful to hover over the present scene’. Apple went on to stage neon shows at the Pepsi Cola Exhibition Gallery, New York, in 1966, and at Howard Wise Gallery, New York, in 1967. His fascination with neon would prove crucial in his transition from making discrete objects that contributed to the evolving language of pop in the 1960s to his process-oriented work of the early 1970s.

Although he never made any more rainbow works after his 1965 show, for HemisFair’68, the 1968 World Fair in San Antonio, Texas, he proposed constructing a giant neon rainbow to span a lake.