A: London, England, United Kingdom, B: Brooklyn, New York, United States
On October 22, 2009 Lawrence Wechler, director of the New York Institute for the Humanities at New York University, published "David Hockney's iPhone Passion," New York Review of Books LXVI, no. 16, 35.
Hockney had a history of exploiting new technologies in his art:
"Hockney continued to explore other media besides painting, most notably photography. From 1982-86, he created some of his best-known and most iconographic work — his “joiners,” large composite landscapes and portraits made up of hundreds or thousands of individual photographs. Hockney initially used a Polaroid camera for the photos, switching to a 35 mm camera as the works grew larger and more complex. In interviews, Hockney related the “joiners” to cubism, pointing out that they incorporate elements that a traditional photograph does not possess — namely time, space, and narrative.
"Always willing to adopt new techniques, in 1986 Hockney began producing art with color photocopiers. He has also incorporated fax machines (faxing art to an exhibition in Brazil, for example) and computer-generated images (most notably Quantel Paintbox, a computer system often used to make graphics for television shows) into his work" (http://www.pbs.org/wnet/americanmasters/episodes/david-hockney/the-colors-of-music/103/, accessed 01-09-2010).