Riding high

David Hockney’s Yorkshire landscapes show that figurative painting – whether on an iPad or 32 joined

David Hockney’s Yorkshire landscapes show that figurative painting – whether on an iPad or 32 joined canvases – is the most humanly involving visual form.

The cover for the January/February 1977 issue of the New Review was a black-and-white, nude photograph of David Hockney and his friend the painter R B Kitaj. Hockney's studio can be glimpsed beyond the edges of an improvised white cardboard background. Hockney's pelvis has a female breadth. Ron Kitaj is stockier. Hockney is wearing his owlish spectacles, Kitaj a coloured wife-beater, dark socks and gym shoes. Hockney's uncircumcised penis is a slump of tallow. Kitaj's penis is circumcised, a chunky chip-shop vinegar dispenser.

It was a provocation. The witty strapline across the bottom right-hand corner was "A Double Issue". It did not improve the magazine's minuscule circulation. Many newsagents were reluctant to stock it.

The two painters were protesting the displacement of the human figure by conceptual art and abstract expressionism. A dialogue inside asserted the importance of tradition - of a Seurat responding across 300 years to Piero della Francesca. Hockney: "I can't understand why anybody would think it was a ridiculous thing to do, but there are people who'd say, 'You can't do that now.'" Both painters favour skill in drawing and the centrality of representation in art. There is a reactionary tincture that might then have excluded Picasso, one of Hockney's heroes: "It's harder to paint people like they are than to do them like Quasimodo."

Francis Bacon, another manhandler of the human figure, felt the same way. This is Hockney in conversation with Martin Gayford: "Francis Bacon was the first intelligent painter I met who dismissed a lot of abstract art. He quoted Giacometti, who used to say a lot of abstraction was 'the art of the handkerchief' - 'C'est l'art du mouchoir' - covered in stains and dribbles . . . I was rather impressed that Francis had the confidence to say that kind of thing at that time. Loads of people would have howled him down."

It was ever thus - newfangled fashion and old-fashioned tradition. And now? There are no human figures in Hockney's new landscapes at the Royal Academy (until 9 April), though there is a Range Rover, captured with great freedom and exactitude on an iPad. But the concern with current fashion remains. This is Hockney talking to Marco Livingstone in Enitharmon's excellent My Yorkshire: "Even if you say, 'Painting landscape is an old-fashioned thing to do', I didn't think that. I knew, 'Oh no, it's not.' I would argue with anybody."

He would, too. Hockney is a brainy painter, widely read, thoughtful, restless, whose ex­ceptional intelligence is secured by his insider expertise. His mind is intimately aware of what an artist's hand is likely to decide. Secret Knowledge, his print and TV narrative of the artistic use of mechanical aids (lenses, mirrors, camera obscura, camera lucida) long before the official "invention" of the camera, is completely persuasive, despite the reservations of art historians. He takes an Ingres drawing and notices a discrepancy - the head is marginally too large for the body: "if Ingres had moved his camera lucida to get in the clothes, a slight change in the magnification would have occurred, explaining the difference in scale". He then observes a technical parallel between Ingres and Warhol, who certainly used a projector.

This show of landscapes is fuelled by a similar innovative thesis - Hockney's sense that the camera isn't the end of painting, that photography's hegemony is finished. Figure, landscape - his abiding concern is with the nature of representation. In literature, this was the argument about realism. Art is never reality. Art is merely realistic - an imitation, a simulacrum. All representations of reality are constructs, conventions, which undergo continuous adjustment, major and minor.

For Hockney, the camera is only a near equivalent of the way we experience reality. And now we are bored: "visual magic tends to wear out when it is based on the photographic conception of space which immobilises the viewer, distancing him from the view". Painting can achieve a more accurate degree of involvement. Picasso gives us the visual experience of the breasts and the bum in the same plane: "because you could see back and front at the same time, you would not ask yourself, where am I? You were inside the picture."

Hockney's aim is to place the viewer inside the painting. His means to this end is the bigger picture, which gives the show its title. There is, however, a problem with increasing the scale of the painting - joins. Winter Timber (2009) is made up of 15 sections, five by three. The Arrival of Spring in Woldgate, East Yorkshire, in 2011 is made up of 32 canvases. In other paintings, the frames of the individual sections are clearly visible. In the old days, according to Hockney, large-scale paintings were wound up and down in "special studios": "that's how they paint theatrical scenery". Hockney didn't have the advantage afforded to a painter such as David - hence the joins, to which he returns, uneasily easy, in conversation with Marco Livingstone: "Long ago I realised that the join doesn't disturb at all. Your eye fills it in . . . you don't really notice the joins after a while." In fact, you do, with the odd exception.

When Hockney visited China with Stephen Spender, he met a nine-year-old prodigy: "He drew pictures for us, cats, done in the Chinese manner with brushes, which were stunning. Watching him do them was something: the way they were placed on the paper . . ." How you place the image is crucial in art - the image can be cropped, or allowed to luxuriate in space, but it has to be deliberate and unhesitant. It is fatal to miscalculate. Hockney (again referring to the "non-problem" of joins): "If you haven't got a big piece of paper, you use two smaller pieces of paper. Any artist would do that, just stick another piece there." It sounds attractively pragmatic, but we've all looked at drawings that have run out of road and continued, with an impression of ineptitude, on an extra added piece.

I said there were exceptions. Winter Timber is one. The colours are so boisterous, so vehement, that the joins aren't an issue. In the foreground are loud tractor tracks in purple chevrons. There is a dead tree trunk straight out of panto, in pink with navy wrinkles. The standing trees are bright turquoise. The form of the picture is a splayed M. At its centre are three loads of logs next to a pink and grey striped road heading to vanishing point, while the logs river towards you - a spate of gold, intended, I think, to remind the viewer of molten steel, great girders of shuddering metal, at once arranged and chaotic, from nature's fiery furnace. I was unpersuaded. They came across as confectionery-coloured, like lengths of marshmallow, those cylindrical sweets called flumps.

In the big paintings the rhetoric count is high, but the masterpieces on show here are mostly smaller-scale, in an area where Hockney has always excelled - drawings. Timber Gone (2008) is a perfect charcoal drawing of absence, the redolent minimal detritus left by the logs in a clearing, an asymmetrical circus ring of sawdust. His charcoal drawings can be miraculous and certainly superior to the paintings. There is a quartet of paintings entitled Three Trees Near Thixendale through the seasons: summer 2007, winter 2007, spring 2008, autumn 2008. Each has eight panels. They are competent, old-fashioned paintings of the kind you could see in railway compartments in the 1950s. Only the scale is gigantified.

And scale is part of the problem. Look at the brilliant charcoal preparatory drawings on deliciously thick Arches Aquarelle paper, Autumn Thixendale, October 21 (2008) and October 18. Charcoal is a difficult medium but Hockney avoids the coarseness always on offer, achieving instead concentrate, burnish and delicacy. In the foreground the ploughland is thin freehand lines. In front there are a few spindly plants, set down swiftly, economically, suggestively. And notice the line for the road and the other single line for the horizon - both simply set down so that the trio of trees is perfectly placed.

Hockney tells Gayford: "If you were told to make a drawing of a tulip using five lines, or one using a hundred, you'd have to be more inventive with the five. After all, drawing in itself is always a limitation." Compare this effortless charcoal spontaneity with the laboured quartet of the Thixendale trees and their formulaic summer leaf canopies. There is another crucial thing to notice in a further charcoal drawing, October 28 - with its working instructions, "chalk in soil", colour notes and marked-in grid - the appearance of a hill into the right of the composition, presumably to expand the scale. In all four of the Thixendale paintings, that hill is dead space, the pictorial equivalent of a brownfill site, irredeemably dull.

Yet his iPad prints are ravishing, if a little overdependent on the road as a compositional device. They exploit the backlighting of the iPad, a sort of dimmer switch, an underglow that works like the wet white ground in pre-Raphaelite paintings. Room nine is dominated by The Arrival of Spring in Woldgate, East Yorkshire, which again is an old-fashioned picture except for its scale. It aims to capture the explosion of spring and, in a measure, does so. Its main device is free-floating leaves the shape of bicycle saddles, some on big bendy twigs. There is a framing candelabra of branches to the right and left of the painting. (Hockney isn't shy enough of the theatrical Claude Lorrain curtains. In A Closer Grand Canyon (1998), a queer picture in 60 sections that captures the unnaturalness of the canyon, he uses two curtains of nougat-like rock as compositional parentheses.)

The iPad drawings are more charming because they're less insistent. You feel the marks more than you do in the big oil; the Arrival of Spring in East Woldgate image from 1 January has puddles on a pink and mauve road like Calder taking a wire for a whirl. (By comparison, Hockney's watercolours are workmanlike. True, his clouds are good, but watercolour was made for clouds. Not even a Sunday painter could fluff clouds. In Trees and Puddles, East Yorkshire 30.iii.04 the wooden puddles are straight out of art block.)

3 January captures what Debussy, the composer of "Brouillards", called the poetry of fog. Apart from the odd failure (irrelevant scribbles across the picture of 8 January), the iPad prints represent Hockney on a roll, one smash hit after another. In the next room are two large iPad masterpieces, both of Yosemite, in which the single vertical joins are virtually invisible. Yosemite II, October 5th 2011 is like something from a Chinese scroll - an ocean of mist in blue mountains, rendered with breathtaking boldness. I thought of Wordsworth's description of mist on Mount Snowdon at the end of The Prelude: "the sea, the real Sea, that seemed/To dwindle and give up its majesty,/Usurp'd upon as far as sight could reach". A great peroration in paint - except it isn't paint as such. Yosemite III, October 5th 2011 reuses the road curving out of sight, reuses the tree curtains from Claude, but transmits the sublime sensation of the endless redwood mounting the length of the picture and continuing out of sight.

The 11 nine-camera films (on 18 screens) are marvellous, too. They splice the seasons, bring movement to nature - especially the bold callisthenics of a hedgerow cavorting in a stiff wind - and use the join to advantage by exploiting repetition, overlap, disappearance and discontinuity.

So, a qualified success but with splendid high points. Miss the reworking of Claude's Sermon on the Mount - disastrously scaled up - with its wooden worshippers listening deafly to Jesus like playpeople. Don't miss the earlier photo-collages: The Grand Canyon, Looking North, September 1982 and Pearblossom Highway, 11th-18th April 1986. Allow four hours at least. There's a lot to look at, a lot to think about.

“David Hockney RA: a Bigger Picture" is at the Royal Academy of Arts, London W1