Complex sentence: Although traditionally a pottery and wood coating, japanning was the popular (mostly black) coating of the accelerating metalware industry; and by the twentieth century the term was freely applied to coatings based on various varnishes and lacquers besides the traditional shellac.
Split into simpler sentences: Although traditionally a pottery and wood coating, japanning was the popular (mostly black) coating of the accelerating metalware industry. By the twentieth century, the term was freely applied to coatings based on various varnishes and lacquers besides the traditional shellac.