An investigation of the lead tin yellows type I and II and their use in Bohemian panel paintings from the Gothic period

Abstract

Background: Presented article summarizes the results of a broad-based survey on painting techniques used during the High and Late Gothic period in the Bohemian panel paintings located in the collections of the National Gallery in Prague. The work is focused on the specific use of yellow pigments - lead tin yellow type I and type II in the panel painting from the period around 1340-1550. In the scientific investigation supplementary microscopic and spectral analyses were made. A representative range of 57 micro-samples collected from the 36 panel paintings of the 21 Masters and their workshops was investigated by the methods of optical microscopy on polarizing microscope (OM). Molecular analysis of both types of yellow was performed using Raman micro-spectroscopy (RMS). The use of this technique was crucial for the nondestructive differentiation between each type of lead-tin yellow. Results: Thanks to the Raman spectroscopy it was possible for the first time to map the usage of lead tin yellow type I and II in such a broad range. Combination of the analytical techniques brought the knowledge about the morphology of the grains and variability of the use of the lead tin yellows in the Bohemian panel paintings. Conclusions: The contribution offers a systematic view on the outcomes and in a synoptic way consults the results of respective scientific methods. It clearly confirms both the temporally and locally specific use of both types of lead tin yellows. The presented facts are the results of interdisciplinary collaboration among the scientists and the art historian.