Investigations on Fire-Gilding

<p>Fire-gilding is a historic technique for the application of golden layers on a number of different base materials, identifiable by the Hg content of these layers. Considering recent findings, the previously accepted lower limit for Hg content comes into scrutiny, motivating the development of a new, destruction-free identification method independent of the absolute Hg content. During the course of development, we identified a characteristic Hg profile in fire-gildings on Ag substrates and gathered evidence to further corroborate the accept lower limit.</p>