An Art Authentication is not an Art Appraisal ...
It's a common mistake in the US that people thinking that an art appraisal is equal to an art authentication. It could not be more wrong. An art appraisal is an opinion of the value of an item in fair market value or in replacement value. It doesn't engage the responsibility of the art appraiser if the painting is a fake or a copy.
A/ Fair market value: The amount for which personal property would be sold in a voluntary transaction between a buyer and a seller. The auction value is most of the time considered as fair market value.
B/ Replacement value: Replacement value or cost is the price that an entity would pay to replace an existing asset at current market price with a similar asset. Usually the replacement asset is found in a gallery, that's why a replacement value is often compared with a gallery value. This gallery value is substantially as the value in auction, it may as well be double or triple the value of auction.
An art authentication process includes:
Justification of authenticity by comparison with other works by the artist Reestablish the works in the "catalogue raisonne" Comparison with other works made by the same artist of the same period Comparison with other artists of the same period or movement Research about the history, provenance, etc. Reestablish history of the painting Graphology analysis of handwriting Signature analysis On site analysis of painting Eventually study of the pigments Study of the support Study of the manner Wood lamp test
The Conclusion Presentation of the file to recognized expert
Each major artist has his own "SOLE RECOGNIZED AUTHENTICATOR". Sotheby's , Christie's , whatever major gallery doesn't have the authority to give an authentication certificate for an item. Sotheby's and Christie's or any respectable auction house will consult the sole recognized authenticator for an artist before to admit it in their auction. They should do so but we know today that many fakes were sold in these major auction houses. Art experts in general may give an opinion at their own responsibility ( Don't forget that in the US everybody can sue anybody for whatever reason..), for which they can be sued if the sole authenticator refuses to authenticate an artwork. In the US because of this possibility to sue an individual or an organization several major institutions so the Warhol-Pollock-Haring-Dekooning-foundation decided to stop the service of authentication. For these painters, if you didn't became an authentication before they decided to close the authentication service there is one solution left: making a file that proves the authenticity of the item with indisputable and verifiable arguments.