Chemistry in the Corner: Investigating the Composition and Origin of Pigments Within Nineteenth Century Swiss Stamps
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Document Type

Poster

Publication Date

Fall 10-1-2026

Abstract

Often tucked into the corner of an envelope and easily overlooked, stamps are significant cultural artifacts. They reflect the cultural and emotional values, technological capacity, and economic conditions of the societies that produce them. While previous studies have focused on analyzing the chemical composition of Italian, English, and Portuguese stamps, this study examines eleven Helvetia Swiss stamps (six red and five yellow stamps) purported to be produced in the late nineteenth century. Through this analysis we seek to (1) determine the compositions of the pigments used in these stamps, and (2) establish whether these pigments are organic or inorganic. Using this information, we hope to constrain printing dates and the materials used in their production. By employing non-destructive techniques such as Scanning Electron Microscopy with Energy-Dispersive Spectroscopy (SEM-EDS), we determined that the majority of the pigments in the stamps are inorganic. Specifically, in the red stamps, lead chromate (PbCrO₄), vermillion (HgS), and red lead (Pb₃O₄) are the most common pigment compounds. In the yellow stamps, lead chromate (PbCrO₄) is the most predominant pigment. These results are consistent with recent studies of Swiss stamps that were printed between 1880 and 1900. Characterizing the composition of historical postage stamps provides valuable insight into the materials and technologies used during their production, as well as the origins of artistic pigments. It also offers a window into the everyday exposure of past populations to hazardous chemical compounds. More broadly, these findings demonstrate how seemingly ordinary objects can preserve important information about the technological, environmental, and cultural history of a society.

Department

DePauw University; Department of Geology & Environmental Geoscience

Project Mentor

Ken Brown

Funding and Acknowledgements

Funded by the DePauw Faculty Development Committee.

Chemistry in the Corner: Investigating the Composition and Origin of Pigments Within Nineteenth Century Swiss Stamps

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