A 365-foot-long painting depicting the battle at Gettysburg is being restored in a mammoth conservation effort. “One part art and one part commercial venture when it opened in Boston in 1884, this colossal canvas, now in Gettysburg, has become as ragged as an old Army tent – worn, torn, sagging and covered in grime. Art conservators here are embarking on a $9 million federally financed project to restore vigor to a painting that has lost its visceral power. On Sunday the cyclorama and the sound-and-light show that brings it to life will close to visitors at the Gettysburg National Military Park for two years of renewal.”