First insight into the artistic materials of Willi Baumeister´s paintings using in situ non-destructive multi-analytical methods

Abstract This paper provides a first insight into Baumeister’s painting materials as part of the project “Innovation or Replacement? Art Technological Investigations of Willi Baumeister’s Paintings (1930–1955)” . A non-destructive, in situ multi-analytical approach, combining multiband technical imaging, hyperspectral imaging (HSI), macro-X-ray fluorescence (MA-XRF), external reflectance Fourier-transform infra-red spectroscopy (ER-FTIR), as well as in situ Raman spectroscopy, was applied to three selected discarded paintings (‘fragments’) representative of his artistic activity. The analyses identified both traditional and unconventional materials, including organic substances such as oil, cellulose nitrate (CN), polyvinyl acetate (PVAc) and possibly buttermilk. The findings are consistent with archival and written sources confirming Baumeister’s experimental engagement with semi-synthetic and emerging synthetic materials. They also establish a solid analytical foundation demonstrating the potential of non-destructive methods for characterising materials in modern paintings.