Selling wallpaper is not easy. At one point, decorative wall-coverings were considered a sign of mediocrity by style gurus. Then it came back in, and went out again, precipitating a fall in prices.Only company that are up on the latest trends can survive in this business. Rasch, a family firm has been printing wallpaper for more than a century. Even the famous Bauhaus wall-coverings were created by Rasch. A report by Dagmar Zindel