Auction introduction: ‘It was a wonderful Spring’, David Hockney recalled in the summer of 2011, ‘And we always planned to record it; I just didn’t realise the iPad would be part of it then.’ He was speaking shortly after he completed an epic work in what was then a very new medium. Early the following year this series of over fifty pictures filled the grandest gallery in the Royal Academy. Hockney entitled this monumental, multiple work, ‘The Arrival of Spring in Woldgate, East Yorkshire in 2011 (twenty eleven). Hockney’s initial idea had been to paint the season of new growth as it evolved from day to day. But working at an easel en plein air, he reflected, was ‘a bit difficult when you are stood out there in the winter’. After he had made a ‘four or five’ iPad drawings on Woldgate in early January, it struck him that ‘we could do the whole room in this way, the iPad would be very good for it’. Between January and June he did 94 iPads, but he edited them down to 51 – of which the 17 in this collection include many of the finest. Martin Gayford