Dr. Olivia Kuzio

Fleeting Flowers: Reimagining the Violet that Vanished from Van Gogh’s Irises

Recent scientific examination of Van Gogh’s Irises revealed that the painting’s iris flowers, which today appear blue, were once purple. A key finding of the study was the identification and mapping of the light-sensitive red pigment geranium lake, which was mixed with three blue pigments—cobalt blue, ultramarine, and Prussian blue—to create the various shades found in the irises. When initially applied, the mixture of red geranium lake with the blue pigments would have created shades of purple. But, how purple?

A team of conservators, scientists, and imaging specialists collaborated to create a 1:1, 3D physical reconstruction of how the painting may have originally appeared. Optical microscopy of a cross-section sample revealed a glimpse of the unfaded purple paint mixture shielded beneath the surface. However, reimagining the full range of purples could not be simply extracted from this single visual point of reference.

To address this, we turned to color science. By modeling the optical properties of the unfaded pigment mixtures (as determined from chemical analysis), we created a series of tone palettes with known relative pigment concentrations—similar to paint swatches from a hardware store. These palettes bracketed the gamut of purples Van Gogh could have reasonably mixed up. Starting with the relative amounts of geranium lake and blue pigments observed in each paint stroke, we selected ranges of purple tones from the palettes and recolored the brush strokes accordingly. The result: vibrant purple irises with intricately gradated tones, rendered through scientific modeling and applied with artistic sensibility.

In this lecture, I will discuss, through the lenses of color and vision science, how our interdisciplinary team linked the analytical and aesthetic understanding of the faded flowers, enabling effective communication, consensus, and reimagination of “how purple” the irises originally were. I will then use the findings and implications of this case study to pose broader questions about works of art as objects with “lifespans:” the ways in which they age, change, fade, and decay in the same way that we as organic creatures do, and the practical and ethical challenges this poses to the fields of conservation and museum science.