Eric Ravilious: Green and pleasant land

It is an alphabet of things. It is like a childhood landscape, but with a very refined technique. It is one version of the English view, and at the very opposite end of Constable and Turner, with its stirring moods and thick lights. This earth and sky offer a very wide and clear sight, and each river, hill, wood has its shape. But there is also something mysterious in his art, something modernist too, and even a kind of wit. He is almost a great artist, and he's just about famous, and his curious name is memorable: Eric Ravilious.

I can't imagine his art travelling outside of England. His native land was the south coast, and specifically Sussex – but unlikely to cross the channel. This is a world with local gods. Ravilious had a short life (1903-42) and he died as a war artist over Iceland. But the South Downs, the curves, are what his handiwork is strongly drawn to. This became, in the mid-30s, his main stamping ground. And if you don't like this provincial vision, you may find in it simply naivety and safety and delicacy. But you can see it differently. His art is just at the limit of some necessary excess. This landscape has a cutting edge.

There are two exhibitions this summer, in the vicinity. There is Familiar Visions at the Towner Art Museum in Eastbourne. It concentrates on his Sussex works, alongside the photography of his son, James Ravilious (1939-99), taken in Devon. And then there are his Ravilious Woodcuts at Charleston, the well-known Bloomsbury farmhouse. Both shows have a too narrow focus.

The son's photographs are dull. It's a school of very confined documentary, preserving the old village ways, when they were taken in the 70s and 80s. Perhaps it doesn't want these pictures to look too lively, otherwise it would suggest a still surviving life. There are churches, hayricks, orchards, thatch, and they are not saying picturesque at least. These scenes declare forlorn, hopeless, gone. Fair enough. But if there hadn't been any connection with the father, who would care?

And as for Eric's woodcuts, these images are very high craftsmanship, but again they are minor creation. They are essentially book-plate emblems, with at best an antiquarian charm. They are heavily blacked in, decorative, heraldic, cramped and neat. The figures are wooden. The views are artificial. The subjects are either stiff or twee. Avoid them. It's the sort of thing people like to take classes in.

Ravilious' paintings, on the other hand, that's to say his watercolours – this is where you find Sussex's freedom and force. It's a pity there are not more of them on display. It would be good to see other parts of the English countryside, and the war images too. But Sussex views offer the essential works. They show his many skills and surprises. They have play.

Take the minimal view of Downs in Winter, for example. It's almost nothing. It's open ground, made of ploughed fields, rolling hills, in his subfusc colours, punctuated by a single far copse – and one bit of foreground agricultural equipment. So is this a modernist scene? Well, it is and it isn't. The land is almost cast in abstract or geometrical forms. There are echoes of Paul Nash, and he learnt from him.

You can imagine the landscape shaped into solid hummocks, in which everything is rounded and reduced, and using the modernist language. But Ravilious' views are never quite streamlined or cut out. The profiles of the hillside are sensitive. The gentle slopes are particularised. You can feel along the horizons' edge.

Or take The Wilmington Giant, one of his chalk figures series, cut into the hillside. Perhaps there's a suggestion of a real deep ancient power, with a ritual upright memory. Perhaps it is only a well-known view of a touristic attraction. Ravilious doesn't seem to worry either way. He's more interested again in play – between the broad, smooth uniformity of a view and the chaos of minute detail.

See the black barbed wires and the rusty fences, strung across the grass and sky. These knotted, twining, wiggling lines crawl over the landscape – and make a contrast, too, against the fat white rounded drawing of the hill figure. Elsewhere, there are telegraph poles with lines running across the skies. Or in the earth, there can be similar marks, in threaded ruts, curves, kinks. The contours are peacefully pregnant: against them, there are bits of jagged stuff, trash, junk.

In nature itself, Ravilious puts smooth against rough. The broad soft land is dotted with spikiness. He seldom shows branches thickly filled with leaves. He prefers bare twiggy trees sticking up. And for a quite different smooth-rough effect, look at Beachy Head. The dominant cliff spreads left and right in curves. But in the middle of the white cliff, a long zigzag edge snaps off.

Of course, there is nothing alien in these views. There is nothing troubling, in terms of strong realism or streamlined modernism or weird hauntings. This world is perfectly homely. But there is a kind of fiction here, suggesting characters. The Waterwheel, for instance, holds an individual. At the front of the scene there's a piece of machinery – tall, upright, solitary, spare – a kind of pylon, turning and catching the wind. It is a standing figure, with a determined head.

And there is also a more subtle individual. The whole background is a recumbent character, a complex dance of interweaving fields, rising up, dipping and swelling, almost like origami. Likewise, there is the dance of Cuckmere Haven. This river sits flat and wide in its valley, a convoluted, undulating bending-winding channel of the waters. With its sharp s-edges, it's like the elaborate signature of a hand, or the mouth of a face.

Most of Ravilious' views are man-made – including fences, machines, buildings, clumps of trees, posts, roads, waterways, ploughs, fields. And even when they're not, these entities are very clear, very shaped, and like something from a story-book. That's to say, these elements of a scene are almost personified. It is a trim and innocent vision.

But then there is another else, another dimension, simultaneous with his images and his shapes. It emanates from the making of his painting. It's the subliminal presence of his work, whose effect is all over – and it's something intense, radiant. It's the way that most of these watercolours are created out of streaks. They're scored, striated, cross-hatched in separated paint strokes. The world is never blurred and never solid.

You can feel it as breathing, the ventilation of this surface coming through. Or you can see it as brightness breaking out, transforming Ravilious' palette. It has its range of very subdued colours, drab, stone, moss, of course, and they're beautiful, but they'd be tasteful if they were fully filled in. The streaks open out these colours, and illuminate them. But more than that, these streaks give a sense of cut, fracture, incision. The grain goes through it like a knife. There is a hint of violence.

The landscape, the ground itself, is not made of substantial earth, but of air and light. And maybe you may say that here's a revelation on the Downs, another familiar English vision. But the technique has an extra turn. The white page is there. It lies visibly beneath the image. It appears through the scene from behind. This landscape is thin, see-through and vulnerable. One expects mother-nature Sussex to be lovable and safe. The surprising thing is, it's not. There is a fierceness in his painting.

Familiar Visions, Towner, Eastbourne (01323 434660) to 5 September; Ravilious Woodcuts, Charleston, East Sussex (01323 811265) to 30 August

For further reading: 'Eric Ravilious: Memoir of an Artist' by Helen Binyon (Lutterworth Press, £28.25). Order for £25.45 from the Independent Bookshop: 08430 600 030