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Of course an art dealer is expected to vouch for the authenticity of the artworks he or she is selling. However, as the market prices for art have exploded, the status of the art expert has attained a significance that far exceeds the responsibilities of the ordinary art dealer.

In the course of the gradual publication of oeuvre catalogues of important artists of the past centuries, we have come to think that for each artist there is one expert who can decide on the authenticity or inauthenticity of works that form part of the oeuvre in his or her charge. Therefore, this designated expert receives from the auction houses the relevant artist's as yet unregistered works for evaluation. If the report is positive, the work will be sold as authentic on the basis that, i) will be included in the oeuvre catalogue which is being established, ii) that will be included in a supplement to any existing oeuvre catalogue, or iii) that comes with the expert's certificate of authenticity.

However, experts are only human; occasionally they may be partial; and they may be in error. As the painter Max Liebermann so famously said, it is the art–historians’ task to declare our bad paintings as fakes – a clear illustration of the situation. It would take too long to list all the criteria that must be considered before a serious expert may call a work of art a fake. The consequences are even more complex when a completely unknown work comes to be acknowledged as authentic.

Since Paul Cézanne’s oeuvre catalogue was published, I have been considered the expert on this artist. In the course of the past twelve years, I have received requests to testify to the authenticity of putative Cézannes that fill ten large filing boxes, with not a single painting among them whose attribution to Cézanne would have been obvious.

Nevertheless, I am quite happy to evaluate all those paintings on the following terms and conditions:

I require a photograph of the work (in colour if possible), which I will keep in my archives once the evaluation is complete.
Unless further examinations are required, the evaluation is free of charge.
I will express my opinion as quickly as possible; it will be prefaced by the remark, "In my opinion," to indicate that I do not consider my verdict to be absolute; however, this will not prevent me from making my evaluation "to the best of my knowledge and ability".


The second artist on whose works I am consulted on a regular basis is Vincent van Gogh. The world's top experts are at the Van Gogh Museum in Amsterdam, and I point out this fact whenever I receive a request. My dear colleagues in Amsterdam and I are on excellent terms; however, there have been instances when our opinions have differed.

In conclusion, I would like to say that any oeuvre catalogue – as any study on an artist – constitutes a contribution toward art history, increasing and improving our current state of knowledge. However, absolute certainty can never be achieved. Each researcher has his or her own approach to "their" artist. For Jan Hulsker on Van Gogh, for example, it was his letters and their dates; for me it has been early provenances. Thus we all work, each in his or her particular field of expertise, with the same ultimate goal: to ensure that the artist is always granted his or her full rights.

© Translation from German, August 2008: Margret Powell-Joss



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