Before buying a work of art, four fundamental questions must be answered: authenticity, condition, fairness of price and the seller's title. Due diligence is the process of analysis that answers these questions. For attribution and authenticity in particular, it relies on three interdependent pillars.
1. Connoisseurship (stylistic and expert examination)
This is the visual analysis carried out by a specialist in the artist, who assesses the handling, the typical materials, the compositional choices, the habits of signature and the recurring anomalies. Although it is the oldest and most indispensable tool, it is a critical judgement that depends on the scholar's independence and on the possibility of comparison with works of certain authorship. Attributions may change over time as historical research progresses.
2. Historical and documentary reconstruction (provenance)
This concerns the traceability of the chain of ownership from the work's origin to the present day, including passages through galleries or auctions, exhibition history, citations in catalogues raisonnés, and labels and stamps on the reverse. A documented and verifiable provenance is a strong indicator, but it is rarely sufficient on its own: paper documentation is often easier to forge than the work itself.
3. Scientific and technical analysis
This draws on diagnostic investigations (X-radiography, reflectography, ultraviolet fluorescence, and chemical analysis of pigments, binders and supports). A fundamental principle applies here: science rules out, it does not prove. The presence of a pigment marketed after the artist's death shows that the work is a fake; conversely, the compatibility of the materials with the period proves only that the work could be authentic, without guaranteeing its authorship.
Combining the evidence and handling uncertainty
The three tools balance and correct one another: the expert eye can be deceived by a refined forgery, a provenance can be fabricated and diagnostics can be circumvented with period materials. Applying them together reduces the margin of error to a minimum and makes it possible to set out the elements of uncertainty transparently; these must never be concealed.
The role of the coordinator
The art advisor or appraiser who manages the due diligence does not issue the opinion on authenticity directly, but coordinates the whole process: requesting opinions on authenticity from the artist's archive, foundation or heirs, and commissioning analyses from independent laboratories. Their task is to assess the overall strength of the three checks and present the client with a clear and protective assessment.