First insight into the artistic materials of Willi Baumeister´s paintings using non- destructive multianalytical methods

This study forms part of the project “ Innovation or Replacement? Art Technological Investigations of Willi Baumeister’s Paintings between 1930 and 1955 ,” which aims to systematically examine the German artist’s artistic practice and material palette. A key question within this context is whether Baumeister’s use of semi-synthetic and synthetic materials was driven by necessity—he faced significant material shortages under National Socialism and was labeled a “degenerate” artist until 1945—or whether it reflects a deliberate artistic strategy. A non-destructive multi-analytical approach using portable imaging and punctual analytical techniques such multiband imaging, hyperspectral imaging, macro x-ray fluorescence, FTIR in reflection mode as well in situ Raman spectroscopy, was followed to gain initial insights into the materials used by the German artist on selected discarded paintings—so-called “fragments”—that are representative of his artistic activity between 1930 and 1955. Binders and additional organic coatings such as oil, cellulose nitrate, polyvinyl acetate, and buttermilk were identified. Moreover, the pigment palette was investigated alongside the visualization of hidden features. The findings are consistent with archival and written sources, highlighting Baumeister’s experimental engagement to newly developed materials. Notably, buttermilk was identified—reportedly for the first time—as a matt agent in an artistic context, underscoring his unconventional material choices. The dating of the paintings, based on stylistic features and the identification of the afore mentioned semi- and synthetic binding media, corresponds with the historical introduction of these substances to the market, indicating that Willi Baumeister remained attuned to contemporary developments in the materials industry. The application of non-destructive analytical techniques has proven effective in providing valuable insights into the complex composition of these works. The results lay the groundwork for further research, including the investigation of micro-sampling by means of micro-invasive analysis, to deepen our understanding of artist’s material composition.