Books on David Hockney, ranging from the classic David Hockney by David Hockney of 1976 to countless Hockney catalogues, are frequent reminders that he commands attention. What a one he is for switching focus and skewing perspectives – widescreen one year, iPad the next. What a demon he is for addictions such as smoking and painting. Were he to accept a knighthood, which is unlikely, he could emerge from the Palace, light up, and declare himself a true successor to Sir Peter Paul Rubens. His pertinacity is as engaging as his zest for new means and new ends.

The Hockney of caricature – hair bleached, gadding abroad from Kensington Gore to Muscle Beach – has become a greying figure. Bridlington is his manor, his hinterland the Yorkshire Wolds. Once so golden, so twinkle-toed, he now addresses the nation as a national treasure should, getting us to recognise in paintings of suburb-an avenues and may-blossomed lanes the lineaments of a renewal. It’s not so much the transfer from Los Angeles to East Yorkshire that’s so striking; it’s the pitch of his enthusiasms, his zeal for apostrophising the seasons, for harvesting the very nature of sparsity, growth and profusion.

I remember him once at a gala dinner in downtown Los Angeles getting up and telling an audience that what they missed, indeed couldn’t know about living in LA, was that wonderful annual occurrence in London parks: the onset of spring. Already by then he had rediscovered the Yorkshire of his childhood and was about to redirect himself into what has become his late-flowering Bridlington Period.

This latest Hockney biography, by Christopher Simon Sykes, is presented as ‘The Biography’. The first volume ends in the mid-Seventies, round about the time Nikos Stangos was taping the reminiscences that went into David Hockney by David Hockney. What does Sykes add? Other voices, for one thing, plus documentation. From ‘Wellington Road School Reports. Hockney Archive. Bridlington’, he gleans the comment: ‘David has shown great interest in his work.’ If this sort of thing adds little to what Hockney himself has already told us, it’s good to learn more about his art-school days in Bradford and at the Royal College, and to have different points of view from those of the sitter, so to speak.

As Hockney becomes cosmopolitan, adept in the ways of the art world, the biographer struggles to keep up (‘Bradford seemed a long way away now to David’) and resorts to travelogue: ‘Hockney took Schlesinger and Clark with him to stay at the chic old Pavillon Sevigne hotel, in order to take the waters, and they drove down in a Triumph Vitesse, bought on the advice of Keith Vaughan’ and so on. It’s period detail, though, and a neat way of introducing Vaughan, Hockney’s glum forerunner in the pictorial genre of men for men’s sake.

Social intricacies fill the pages, keeping track of Hockney’s full diary of engagements and excursions in the years before loss of hearing began to afflict him, particularly in crowded rooms. What’s missing, however, is any real sense of his Rubens-like qualities: the overarching nature of his output, and his ability to turn his hand to anything from posters to murals to costume designs to formal portraits and nifty skits. If there is to be another volume, Sykes will have to adapt to catch up; for Hockney’s art, his constant resource, is what he is all about, actually. Indeed, ‘actually’, Hockney’s favourite adverb, says it all: that sense of being onto things, questioning every standard approach, and spotting imaginative possibilities. Painting dictates his moves, always has done, even when he went venturing into the deconstruction of photography, as he did for rather too long. And no Hockney biographer should be allowed to get away with descriptions of his art that read like tour guide patter, such as ‘a picture that is awash with tension’.

Martin Gayford’s take on Hockney is, as he sees it, layered. He has assembled several interviews conducted with the artist over the past ten years for magazines and newspapers, topping and tailing them with commentary and adding personal notes reminiscent of Jennifer’s Diary: ‘In a little two-coach train bound for Scarborough, I found a deputation from the art world: Norman Rosenthal of the Royal Academy, his wife Manuela Beatriz Mena Marques of the Prado, and their two daughters, plus Hockney’s London dealer David Juda and his wife.’ Strip such layers away and, as generally happens with Hockney books, that engaging voice of the artist himself hogs the microphone and delivers:

When I’m looking at your face now, it’s rather big in my vision because I’m concentrating on you and not on other things. But if I just move for a moment to look over there, your face becomes small. Isn’t that what is happening? Isn’t the eye part of the mind? If you look at Egyptian pictures, the Pharaoh is three times bigger than anybody else.

And on he goes, drawing far-flung comparisons and posing questions that demand smiles of assent. Photography is given the runaround. Some time ago he was all for it, when trying to extend its range, but more recently he has been exasperated with it. He recalls seeing four big photographs at Tate Modern as he was leaving the great ‘Matisse/Picasso’ exhibition:

I walked up to them because they don’t read across the room that well, looked at them and I thought, ‘Fuck me, Picasso and Matisse made the world look incredibly exciting; photography makes it look very, very dull. Yet now we are moving back to all the stuff that modernism moved away from.’

Hockney seems happy at the moment to surrender himself to the delight of being able to replay the act of drawing something on an iPad, right down from the first mark. The thrill may wear off, but there’s always the pleasure of trying for further app effects. ‘You miss the resist of paper a little, but you can get a marvellous flow. There are gains and losses with everything. So much variety is possible. You can’t overwork this because it’s not a real surface.’

I look for the usual affirmative ‘actually’ but it’s not there, having been edited out or left unsaid. Hockney’s recent infatuation with Steve Jobs’s final baby, and the kick he gets out of transmitting colourful images to all his contacts, are several steps on from the days when, to him, a fax machine was a magic lantern of possibilities. Funny how the more he talks, the more he carries on with new kit, the stronger the flashbacks are to landscapes of old.