From the Greek word chrysographia, meaning 'writing in gold', chrysography is the use of powdered gold, mixed with glair or gum (see binding medium) to create an ink; when dry, the ink is usually burnished (see burnishing). Gold (and silver) writing on parchment is known from the Early Christian period on. Purple pages were introduced in Byzantine books at least as early as the sixth century as a more suitable and luxurious background for such script; the imperial connotation of having been 'born to the purple' was implicit in the ostentatious use of the colour. Chrysography was practiced in Insular, Anglo-Saxon, Carolingian, and Ottonian luxury book production and also occurs sporadically later in the Middle Ages and the Renaissance. Gold ink was also used in Byzantine illumination to provide highlights (especially in articulating drapery) and other details, a technique transmitted to the West, where it enjoyed particular popularity during the fifteenth century. Chrysography in late Gothic art is often somewhat formulaic and mechanical, but it achieved great refinement in panel painting and within Renaissance illumination.