Hockney discovered drawing on his iPhone in late 2008. He told a reporter in 2010 that he drew flowers every day on his iPhone, sending them to friends so they got fresh flowers every morning; he said the gadget made his flowers last longer than fresh ones.

"When I paint, I feel like I'm only 30. That was what Picasso said. And I feel the same way. I feel down when I don't paint, because I don't know what to do other than to paint."

Some critics have suggested that Hockney's works produced during his return to Yorkshire are not equal in creativity to his earlier works, especially after his move to Los Angeles in the 1970s.

"I'm still quite an active artist. I don't live in the 1960s or '70s. I'm living the moment and all artists should be the same," he says. He is categorized as a member of the Pop Art movement, a label he rejects.

The artist is currently preparing for a upcoming solo exhibition in London. He will display some 60 portraits - he says only two or three of them have previously been exhibited.

His photo collages will also be there. He displayed some slides from his latest productions at the talk in the Central Academy of Fine Arts in Beijing.

"I talk a lot about photography ... but photography documents, in a flat, bored way and provides a single perspective," he says. He showed a slide at CAFA that read, "Photography came out of painting ... and it is now going back to it."

He pieces together photos taken from multiple angles to form new pictures. It generates an unusual yet impressive visual effect by which he informs the viewers of the possibilities of perspective.

"One can always find in the traditional things (like painting) something that is essential and can carry on ... There is always a new perspective to see the world. Just