The Visual Difference in the Double Portrait of Marie and P.S. Krøyer: An Investigation of Materials and Paint Layer Stratigraphy

In 1890, the newlywed artists Marie and P.S. Krøyer painted each other on the same canvas. Today, the two portrait halves appear with a clear visual difference in tone. 
Why?

This thesis investigates the visual difference currently observed in the Double Portrait of Marie and P.S. Krøyer (1890), in which the two artists portrayed each other on the same canvas during their honeymoon. Today, the background surrounding Marie Krøyer appears more yellowish, while the background surrounding P.S. Krøyer appears more bluish in tone. The results suggest a dual ageing effect in which each half of the painting has gradually shifted in a different visual direction over time.

XRF, SEM-EDX, GC-MS, Py-GC-MS and micro-FTIR analyses, combined with microscopy and analytical photography, demonstrate that the two portrait halves are based on broadly similar material compositions dominated by zinc white and cobalt blue, while differing in paint layer stratigraphy, colour mixtures and binding media.

The bluish half appears associated with fading of red lake dyes combined with the high light stability of cobalt blue and a less yellowing binding medium, whereas the yellowish half appears more consistent with the use of a more strongly yellowing binding medium.

The analyses further suggest that the painting originally appeared more visually unified, possibly with a muted lilac background, and that the painting process was more dynamic and alternating between the two portrait halves than previously assumed. Early signs of metal soap formation identified in the upper zinc white layers may additionally contribute to future translucency and continued visual change over time.

The thesis demonstrates how ageing processes within specific material combinations have significantly shaped the current appearance of the Double Portrait and points to implications for understanding visual change in other works by Marie and P.S. Krøyer.

More broadly, the thesis contributes to ongoing discussions on how conservation and material analysis may deepen the art historical understanding of paintings by revealing how their present appearance can differ significantly from the artists’ original intentions, while also supporting future conservation strategies aimed at mitigating further visual change over time.