Colourful Cities of the World – A Case Study

Abstract

This article presents the technical examination and conservation of a hand-coloured copy of the fourth volume of “Civitates Orbis Terrarum” (1588), edited by Georg Braun and engraved primarily by Franz Hogenberg. The atlas held in the library of the State Archive Hamburg (shelf mark W 120/804), exhibited structural damage to the binding as well as numerous tears and previous repairs within the map sheets. During the initial examination, green-coloured areas with a velvety, matte, powdery-looking appearance raised health and safety concerns regarding the potential presence of arsenic-containing green pigments. To assess potential risks and identify the pigments used in the colour layers, a non-invasive micro-X-ray fluorescence analysis was carried out. The results disproved the initial hypothesis for the green areas, identifying them as copper-based pigments. However, the analysis unexpectedly revealed a considerable arsenic content in the visually stable gold- and some yellow-coloured areas, consistent with their identification as orpiment. The analytical results informed both the conservation treatment and the handling recommendations for the atlas. This case study illustrates the importance of integrating material analysis, risk assessment, and conservation practice when dealing with hand-coloured early modern prints.