Eastern promise: George Chinnery

Though he lived in India and China 200 years ago, a rare exhibition of work by the painter George Chinnery shows his modernity

To us, the experience of empire may have been about power, commerce and occupation.

To many British people at the time it was more a matter of escape, from poverty, family or creditors. In the case of the artist George Chinnery, it seems to have been a combination of all three.

When he sailed for India in 1802 he left a wife and children, who didn't join him for 16 years, and very probably, given his form, a pile of debts. He didn't change his habits. After two decades in India, creditors again forced him to up sticks and move, this time to China in 1825. There he remained for the rest of his life – he died in 1852.

In that, he was unusual. Debt and artists were not an uncommon combination. But most of the painters who went out to India, such as Thomas and William Daniell, William Hodges and Johann Zoffany, went for just a few years, to build up a body of portraits to sell there and views to bring home. Chinnery was different.

A great bon viveur, he too tried to make his way through the combination of painting local British dignitaries and romantic ruins. But as a revealing exhibition at Asia House shows, he was in some ways much more of a modern artist than the more famous painters of British India – fascinated by the life around him, he was far more impressionistic in his painting.

Asia House calls the exhibition The Flamboyant Mr Chinnery, and promotes it with a picture of the artist painting an army sitter that is in a caricature style that owes much to George Cruikshank. It does Chinnery a disservice. To his contemporaries, true, he had the reputation of a rake, a good drinking companion fond of the high life, women and wit. But although he painted some jokey scenes of his studio to give himself a bit of a dash, caricature wasn't really his style. His sketches and their accompanying notes in shorthand show a serious artist, deeply committed to his craft.

His pictures of worthies such as Sir Henry Russell, Chief Justice of Bengal, George Siddons and William Jardine are skilled enough in the manner of Reynolds, with a touch of Lawrence. But one is never quite sure that his heart is in them, until one comes across The Kirkpatrick Children. It is a work on the grand scale but it is also a painting of peculiar poignancy, melancholy even.

The boy and girl are children of Colonel James Achilles Kirkpatrick, resident at the court of Hyderabad, who set up home (to some scandal amongst his fellow Europeans) with the Indo-Iranian great niece of the Nizam of Hyderabad's chief minister. The two children, four and three years old, are dressed in the costume of the court but look singularly unhappy. They had reason to be. Soon enough they were shipped back to England for baptism and given Christian names, never to see their parents again. There is a sympathy in the way Chinnery presents them, the boy looking straight at the viewer with a self-conscious stance, hand on hip, and the girl looking uncomfortably at the floor, that is rare in portraiture of the period.

That human sympathy is seen to even more effect in the portraits of two Chinese merchants, Mowqua and Howqua, done when Chinnery moved to Macau some 20 years after he painted the Kirkpatrick portrait. At the time, westerners were restricted in their access to China, trading out of settlements in Macau and later Hong Kong, where Chinnery also went. They had to deal through a group of local merchants known as the "co-hong."

Chinnery's portraits warmly communicate both the prestige and the character of the leaders of these merchants: Mowqua is popular and outgoing, the more senior Howqua watchful but engaged. Such work changed the style of local portraiture by Chinese artists, but it also marked out Chinnery as a painter of genuine talent.

Chinnery's interest in the local scene does indeed set him apart from most western artists of the time. Right from his arrival in India, you feel his artistic response to the place. A watercolour of Trees in a Landscape sets a single tree boldly against a mountain background of evening light, to startling effect. A delightful pen and ink and watercolour study of Palanquin Bearers Resting is a wonderfully vibrant composition of bearers relaxing but still alert. Others painted ruined temples and mosques with a sense of monumentality; Chinnery portrays them, as in Figures at the Water's Edge by a Ruined Tomb, Bengal, with a sense not just of the picturesque but of people as they wash their clothes and collect water from the river.

With the Indian pictures, Chinnery retains some English landscape feel for vegetation and building. With the Chinese works, he alters his style to something much more Dutch in its depiction of boats on still water and ordinary people at work and play, such as the oil Group of Gamblers at a Circular Table and a watercolour, Blacksmiths at Work.

Asia House, London (020 7307 5454), to 21 January