This analytical technique allows for the non-destructive quantitative characterization by SEM-EDS of the near surface of cultural heritage objects small enough to fit within an SEM chamber that may contain corrosion products, without applying a conductive coating. Using a multivoltage analysis consisting of measurements taken at a series of electron beam energies was obtained and input into a film thickness and composition (FTC) computational model that can characterize a layered film on a substrate. Using the FTC computation, the coating on a French 18th century metal thread was determined to be an alloy 80% Au 20% Ag on a nominally pure Ag substrate, and this matches a minimum gold standard allowed for goods around the time of manufacture. The computed gilding thickness range from the single digit nm to 300 nm depending upon surface inhomogeneities formed during the production of thread.
