Fewer than 90 minutes after it began, the Timber Lake Playhouse's season-opening production of Joseph & the Amazing Technicolor Dreamcoat ended, appropriately, with a blast of exuberant, life-affirming color. Yet at the curtain call for this fantastically well-sung presentation of composer Andrew Lloyd Webber's and lyricist Tim Rice's beloved biblical musical, it became clear that the stars of the show weren't the gifted performers portraying Joseph, the Narrator, or any of director James Beaudry's 19 other cast members. The real stars, it turned out, were the streamers.