Restoration of Joseph Wright of Derby paintings reveals hidden details

Tiny figures and flames hidden for a century re-emerge in paintings due to go back on display in painter's native city Sparks flew when the world's largest collection of paintings by Joseph Wright of Derby was cleaned - along with wind-blown spray flashing in sunlight, flames shooting from mountain tops and tiny figures suddenly revealed skulking in inky shadows. The conservation work on the paintings, before the reopening this weekend of the gallery in his native city dedicated to his work, astonished Lucy Salt, keeper of fine art at the city museum, who thought she knew every inch of the paintings, and suddenly saw details invisible for more than a century re-emerge. Wright remains a bit of a mystery to her. He was born in 1734 a few hundred yards from the museum, a town clerk's son who taught himself to draw by copying prints. Although he went on to study in London, and exhibited at the Royal Academy until he fell out with them because he thought they undervalued his work and chipped his frames, and travelled in mainland Europe where he saw Vesuvius erupting, an experience recalled in scores of his paintings, he spent nearly his entire life in Derby and died in a house almost within sight of his birthplace. Nothing in his life explains the drama and passion in his work which made him famous - although he knew many scientists, inventors and philosophers, and watched the scientific experiments shown in many of his best-known works, including the spellbound group watching a demonstration of an orrery. "There's a really wild streak in Wright. He was very intelligent, and had a very wide circle of extremely interesting and intellectual friends, but he was obviously quite a difficult man, nervous, ill, anxious, increasingly reluctant to leave his house. And yet the paintings don't reflect that at all," says Salt. The gallery owns one of his last works, painted two years before his death at the age of 63, when he had probably already suffered a stroke and was complaining of pain and tremor in his hands. It is a glittering view of Rydal waterfall, in which he achieved his ambition of showing every pebble below the ripples of water, a painting full of light and happiness. Wright commented grumpily in a letter than he was frozen working on it, and never so glad to get out of a wood in his life. It was a critic in his lifetime who called him "Joseph Wright of Derby" to distinguish him from another artist Wright, but the grand title has stuck ever since, much to the satisfaction of his home. Although his paintings are in many major collections, including the National Gallery, National Portrait Gallery and the Royal Collection, Derby started collecting his work as soon as the Victorian museum was built. The first, the Alchemist, was bought by public subscription for