For all its themes of inspiration and triumph, “The Shawshank Redemption” was a rather uninspiring and un-triumphant film when it was first released in 1994. Though critically well received, it did terribly at the box office, taking only $18m in America against a budget of $35m. Though nominated for several awards, it won none. This prison drama, starring Tim Robbins and Morgan Freeman, looked as if it would slide quietly into obscurity, like so many movies. But it didn’t. Through word-of-mouth recommendations it gathered momentum after it left the box office.