Jewelers are trained in an informal system of apprenticeship, and the trade often passes from father to son. In small towns and rural areas, jewelers often work alone, taking responsibility for all aspects of their craft. In larger cities, jewelers typically labor in workshops where they specialize in a particular aspect of jewelry making: molds, granulation, enamel, or kundun, for example. In the past, jewelry guilds established and maintained the standards and ethics of the trade. Premodern records suggest that jewelers sometimes applied their skills to other arts as well, such as sculpture and architecture.