Ancient sculptures were not generally white, in bare marble, as we see them today, but they were painted, colored.

It is probably due to natural deterioration processes that most of those that have survived and we can see today have not preserved their polychromy. Over the centuries, colours have gradually faded or worn away, revealing the marble surfaces, once meant to be hidden.

A relatively modern aesthetic, like that of Winckelmann, and then again of Canova, imagined them to have always been so, making white marble an ideal of beauty and of formal perfection that has continued to influence our perception of ancient statues to this day.

Starting from the 1980s, however, scientific research using multispectral imaging techniques has been able to reveal traces of ancient pigments, or binders still present in small areas or in small quantities, often invisible to the naked eye.

Even the Artemis, from the first century B.C., found near Castiglione della Pescaia (GR), and now under restoration at the Opificio delle Pietre Dure in Florence, was probably originally colored.

On this one, we applied a new method of analysis, presented at the recent Florence Heri-tech conference.

To date, four marble replicas of this type of Artemis are known:
– the version at the National Archaeological Museum of Venice;
– the Artemis statue found in a Pompeii domus in 1760;
– the one found in 1880 in Castiglion della Pescaia;
– The copy seized in 2001 by the Carabinieri and probably found in Lazio or Campania;
The four replicas were exhibited in 2023 at the MAAM in Grosseto in the exhibition “One, None, One Hundred Thousand.”

Interestingly, more statues very similar to this one have been found in Italy, a total of 4. So similar that their measurements differ very little, although the style varies between each. The statue from Castiglione della Pescaia is confirmed to be perhaps the most refined in craftsmanship, despite its missing head.

On the replica of the Artemis discovered in Pompeii in 1760, in a domus between the Forum Baths and the villa of M. Fabio Rufo, many remnants of the original polychromy were detected. These have been studied, and an original polychromy has been reconstructed as in the figure here next, although the reconstruction appears much less elaborate than it likely was in reality.

Art-Test, along with a team involving specialists from the Opificio delle Pietre Dure (IT), Indiana University (USA), CNR (IT), and the University of Padua (IT), has proposed an innovative method to reveal and map residual pigments and binders directly in 3D using multispectral 3D models.

We know that imaging techniques such as UltraViolet Fluorescence (UVF) or Infrared Reflectography (IRR) can be employed to reveal organic materials and conservation conditions, even those not visible to the naked eye.

In the study presented, we used these techniques not only to investigate the surfaces but also to reconstruct, through photogrammetry, separate 3D models, starting from visible images, as well as in UVF and IRR.

The initial images were acquired using a cell phone, making the methodology truly accessible. The various models obtained were then aligned and merged.

Furthermore, we used spectral similarity measures to map areas with similar characteristics across the entire surface.

In practice, through these algorithms, one can select a point on the model and verify where the same characteristics are present on the rest of the statue.

This approach allows for a deeper understanding of the conservation status of the works and visualises it in 3D, as well as planning restoration interventions.

In the case of the Artemis sculpture, the goal is to continue the study, identify points for further analysis, and also proceed after restoration, with a new 3D modelling and mapping.

The results of the work will soon be available in the volume, edited by Springer, where the most important works presented at the Florence Heri-Tech conference will be published.

Anna Pelagotti
Anna Pelagotti