Scientifically dating cavases

Nov 27, 2025 | Authentications & attributions, Studies and Projects

Not only C14, a new method can help uncovering when and where a painting on canvas was produced

Forget about counting threads through a mini magnifying glass or describing canvases using subjective classifications. In the technical laboratories of Museo Nacional del Prado, conservators — working in collaboration with computer scientists — have developed software that performs these analyses automatically using photographsn of the back of a painting or X-rays images. The tool is called Aracne. It does far more than traditional visual inspection.

The original idea was spearheaded by Rick Johnson and other researchers at Cornell University in Ithaca, New York in 2011— notably via a project called the Thread Count Automation Project (TCAP) — and later refined by others, including Belgian mathematician Ingrid Daubechies. The method was initially applied to the paintings of Vincent van Gogh to help establish the chronology of some of his work.

How does it work?

Canvas for paintings was often produced in large rolls, with a weave that—although seemingly uniform to the naked eye—actually contains subtle, distinctive irregularities. These irregularities remain consistent along the entire roll.
By analysing thread density and weave patterns (warp/weft spacing, orientation, irregularities) through, we can generate a “weave-map” or “canvas fingerprint.” If two paintings share that same fingerprint, they likely come from the same roll — meaning they were painted around the same time, or in similar production conditions. See Rick explaining it here.
This is far more reliable and objective than manual and subjective classification of canvas weave or thread counts.

Concrete successes

Using this technique, in the case of Van Gogh the “weave-map” helped validate that certain paintings belonged together — for example, showing that two or more works originated from the same roll of canvas, which provided strong evidence for their authenticity and dating.
At the Prado, Aracne has already yielded important results. For instance, during the 2023 exhibition “Herrera the Younger and the Absolute Baroque,” the portrait known as The Artillery General, traditionally attributed to Francisco Rizi, was re-attributed to Francisco Herrera the Younger on the basis of canvas analysis.
In another case, the dating of a portrait of Philip II of Spain was revised: a work previously dated to 1565 was re-dated to 1573, after discovering it was painted on the same canvas roll as a portrait of Anne of Austria.
For Old Masters: analyses have shown that some copies by Peter Paul Rubens of works by Titian (e.g. Adam and Eve, The Abduction of Europa) were painted in Madrid on canvases cut from the same roll — supporting connoisseurship notions about where and when Rubens was active.