Imperial diptych offerings to the emperor. However, the fact that the Barberini ivory was almost certainly not a diptych, but some kind of imperial icon without a second panel is a serious argument against the existence of the imperial diptych type. The two panels representing the empress Ariadne, in the Bargello in Florence and the Kunsthistorisches Museum in Vienna, also belong to the hypothesied imperial diptych type. They are the only central panels of such a diptych (other than the Barberini ivory) to survive, since all other fragments of such diptychs are from side panels. Imperial diptych In Late Antiquity, an imperial
Early Netherlandish painting both sides or with the reverse bearing family emblems, crests or ancillary outline sketches. In the case of single panels, the markings on the reverse are often wholly unrelated to the obverse and may be later additions, or as Campbell speculates, "done for the artist's amusement". Painting each side of a panel was practical since it prevented the wood from warping. Usually the frames of hinged works were constructed before the individual panels were worked on. Glue binder was often used as an inexpensive alternative to oil. Many works using this medium were produced but few survive today because of