Which artists will define our age?

It glows. The whole painting glows. Glows not just with the way the light from a fire unseen beyond the artist’s frame reflects in his glistening eyes; reflects in the moist redness of his almost girlish lips; reflects in the folds of his turban and silky grey sash. It glows too from an inner radiation, glows from his character.

We have in Britain some arcane tax legislation that can bring a harvest that’s anything but arcane. The recent acquisition of Joseph Wright of Derby’s ‘Self-Portrait at the Age of about Forty’ (c. 1772) has been made possible ‘in lieu of inheritance tax… under a hybrid arrangement and allocated to Derby Museums… with further support from the National Heritage Memorial Fund’. Private individuals like Robert M. Kirkland and other donors and foundations have helped too. The result is that the self-portrait of the great 18th-century artist of the Midlands industrial revolution has come home.

It has just been put on display, the centrepiece of an entire gallery room devoted by the Derby Museum and Gallery to their city’s greatest artistic son. Wright doesn’t just happen to come from Derby and didn’t just happen to live in the English Midlands when Sir Richard Arkwright revolutionised the spinning industry at Cromford Mill, 20 miles up the river Derwent. These realities and this world made him, and made his art. There are such things as soundtracks to an era; there are also artworks that frame it for us – and Joe Wright has that distinction. He brings to us the excitement of scientific and industrial progress.

I went last week to see the acquisition in its new setting. It has been beautifully done. All around the walls are Wright’s paintings: portraits, real and imaginary scenes, landscapes, families with wondering children caught by his brush as they gaze at scientific experiments, blacksmiths at their anvil. And in the centre, ingeniously displayed so you can walk round to the back of it, is the self-portrait: surely his best, self-consciously exotic and dressed up for the role of celebrated master of his art. And the reason you’ll want to see the back is that, to save on expense, he used a canvass he’d employed for a first study for his famous ‘An Experiment on a Bird in the Air Pump’.

I had an hour between trains, and took a taxi to the gallery, giving me about half an hour to inspect. I could have spent that time just staring at the self-portrait. Some paintings need distance, but you can get right up close to this, face to face with the subject. I almost feel I know him now.

Wright painted portraits, of course, for money. But with many of those on these walls one gets the strongest intimation that he knew and had judged his sitter. Look in particular at his huge portrait – the definitive work – of Sir Richard Arkwright; then at his portrait of the innovative Belper mill-owner, Jedediah Strutt (no knighthood because he was a convinced Unitarian). Strutt’s belief in social obligation is still evident in the design and proportions of the mill-workers’ houses he built, and when William Gaskell (Unitarian minister and husband of the celebrated novelist) visited Belper he thought it a shame there were not more factories owned by such ‘men of enlarged benevolence and active philanthropy’. Sir Richard was altogether more ruthless: a hard-driving man. And you can see it in both portraits: Arkwright proud, fat, cocky, domineering; Strutt gentle, thoughtful-looking, with a kind of inner light. And then Arkwright’s son Richard: expensively dressed, wife in a hat with bows big enough to dwarf Liz Truss’s extravagances, her husband almost dandified with a hint of weakness in his face, the rich man’s son.

There’s no doubt that the paintings of industry and scientific experimentation dominate the works. Alone, almost plaintive in the gallery company she must keep, is a huge portrait of an imagined American Indian princess, widowed, out on a hillside keeping watch over the sacred objects of her dead husband’s inheritance. In the sky behind her is the most vivid painting of lightning I’ve seen. Perhaps Joe Wright sensed the portents for her way of life – just as in his beautiful painting of Needwood Forest near Derby, now part of the National Forest but then all but destroyed by an epoch for which, in a sense, Wright was the court artist.

I said earlier that epochs may have artistic backdrops just as they may have musical soundtracks. From the perspective of more than two centuries, it’s easy to see how Joseph Wright of Derby illustrated his era in the Midlands. Two centuries from now, will there be fine art or sculpture that says ‘early 21st-century Britain’ with the confidence that Wright could command?

I cannot say I can see what the candidates might be, but perhaps that’s because we’re in the thick of it, and time will thin down the extraneous to the core. However I do think we can do it now for the 1950s, when I was a boy. That neon fluorescent light-changing installation that used to flash beside Waterloo Bridge in London; Henry Moore’s strange figures; the look and feel of the Festival of Britain on the South Bank; Dan Dare, Pilot of the Future, in the Eagle comic, with his evil adversary, the Mekon; and the germ-free, lifestyle-themed advertising that seemed to usher us into a world of hygiene and vitamins. I used to collect copies of Do It Yourself magazine, where you enter this world: ‘contemporary’ living; clean lines; wipeable Formica surfaces; domestic appliances that banished drudgery. This was a post-war Britain that felt as though we were inhaling the fresh air of modernity. Away with frills and dark mahogany wardrobes; in with fitted cupboards, Nylon and Bakelite.

These, alongside portraiture that had no time for detail and display, or impedimenta around the margins, no time for curtains and cushions and fusty book-lined backdrops, but tried to cut to the chase: these illustrated the age. An age of functionality, an age of reason, was at last upon us. It all feels so dated now, almost like a dead end.