The artists’ materials of P. S. Krøyer: An analytical study of the artist’s paintings and tube colours by Raman, SEM–EDS and HPLC

Abstract An analytical study of two paintings by P. S. Krøyer and the tube colours found in his painting cabinet has been carried out in order to investigate the artists’ materials used by Krøyer in the latter part of his oeuvre. The study has given a valuable knowledge about Krøyer’s choice of materials and their composition that may be helpful in e.g. preservation issues. The pigments and dyes were analysed by micro-Raman spectroscopy (MRS), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM–EDS), and high-performance liquid chromatography with diode-array detection (HPLC–DAD). The technical analyses were supplemented with archival studies of Danish nineteenth century paint shops. The results show that Krøyer used commercially available artists’ materials typical for that period in time. Being a wealthy artist, he seems to have favoured expensive pigments such as cobalt blue, viridian and cadmium yellow. Based on the analyses, the main development in Krøyer’s palette is the substitution of lead white with zinc white that appears to have taken place after 1886. The results also show that the contents of the tube colours in some cases differ from what was expected based on the trade names. This is particularly observed for the tube colours named “Oxide rouge” of which only one contains the expected hematite pigment, while all the remaining contain cadmium sulfide and natural organic red lakes. A rare tube colour named “Laque verte clair” was characterised to be mixture of Prussian blue and synthetic Indian yellow. The study therefore also illustrates that it was not always obvious to the artists what they bought from their colour merchant. It hence relates to existing international studies of nineteen century artists’ materials, which highlight the complexity of tube colours from this particular period in time. Graphical abstract P. S. Krøyer’s portrait of Holger Drachmann and some of the tube colours used by Krøyer.