Another fundamental operation is that of dyeing materials. Until 1860, approximately, the carpets were made of dyed fibers derived from plant or animal world; little more than a century ago were introduced by Westerners artificial colors much more easily achievable and practical for use, but considerably lower for this regarding the strength of the fiber, its color and the possibility of infinite gradations typical operator's craft. In recent years, Iran has been greatly reduced the use of artificial coloring.