At official exhibitions in the nineteenth century, such as the Royal Academy summer exhibition, artists would give a finishingtouch to their works by varnishing them. The custom of patrons and the élite of visiting the academies during the varnishing day prior to the formal opening of the exhibition gave rise to the tradition of celebrating the completion of an art work or a series of art works with friends and sponsors. In the twentieth century it became an opportunity to market the works on view to buyers and critics.