Angels under the scanner

Say you want to restore a painting packed with painterly riddles. Who you gonna call? The AXES research group at Antwerp University!

The first thing you have to do when embarking on any restoration is carry out a preliminary examination. Sometimes, the naked eye and ultraviolet and infrared light are enough to assess an art work’s structure. But other paintings present conservators with all sorts of puzzles. That’s where the team from Antwerp University comes in with its MA-XRF scanner. The Fall of the Rebel Angels by Frans Floris is one such mysterious work: a turbulent history has left all sorts of traces, but which of these are original?

Schilderij Val van de opstandige engelen van Frans Floris
Fall of the Rebel Angels Frans Floris

Turbulent history

Frans Floris painted this immense panel – over three metres high – in 1554. Together with two side panels, now lost, it adorned the altar of the Fencers’ Guild in Antwerp Cathedral. Research indicates that the work had already been restored by as early as 1567. Was it damaged by Calvinist iconoclasts? Were the side panels lost at the same time?

By the 17th century, the existing altar had become hopelessly old-fashioned and so the guild commissioned a new, Baroque version, with sculptures around the painting.

In 1794, the masterpiece caught the eye of Napoleon’s occupying troops, who carried it off to Paris. It was returned to Antwerp in 1815, apparently in good condition, aside from a few ‘wrinkles’ in the middle.

Open questions

1. The left edge of the painting has been sawn down a little. Was this done to fit the work into the new Baroque altar? Or did it happen in Paris? It is no longer possible to say.

2. The trapezoidal piece at the top is darker than the rest of the painting. It is badly damaged and the paint losses were heavily retouched at some earlier date, making it hard to judge whether the upper part is original. The brushstrokes are different, yet entirely in keeping with Frans Floris’ style. The composition looks somewhat truncated without the top piece. Could Antwerp University shed any light on the matter?

Infrarood beeld van het bovenste deel van het schilderij
Infrared photo The trapezoidal top piece is darker in both daylight and infrared. Infrared photo: Adri Verburg.

Pigment research

The AXES research group at Antwerp University specializes in the biological and physical analysis and imaging of materials. It regularly develops new equipment to study paintings, which it uses all over the world. The KMSKA has been working with AXES since the conservation of Memling’s God the Father Surrounded by Singing and Music-Making Angels – another work that posed all sorts of challenging questions.

The research group used an MA-XRF scanner to determine whether the upper part of the Fall of the Rebel Angels was done by Floris himself or added later. The device scans the painting, point by point, using X-rays, which penetrate below the painted surface without harming it. They interact with the chemical substances present there, which themselves emit specific X-rays for the scanner to measure. These measurements are characteristic of a particular substance and so enable the researchers to identify which chemical elements have been used. The scanner also maps their distribution across the painting.

The most commonly used pigments in early paintings contain metals or metal compounds, to which this technique is highly sensitive. There were pigments based on lead, calcium and copper: lead is found, for instance, in lead white, which is toxic. Variations in the use of this pigment can help determine whether or not Frans Floris also painted the top piece himself. And if this is not conclusive, another substance might provide the answer.


The upper part of the Fall of the Rebel Angels was situated too high for the scanner to be used. The panel was therefore checked and then placed on its right edge. The video shows the researchers installing and testing the scanner. Will AXES and the conservators be able to ascertain whether or not Frans Floris painted the piece himself?


To be continued...