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Standards & Guidelines » CAA Guidelines

Authentications and Attributions

Adopted by the CAA Board of Directors on October 25, 2009.

A. Introduction

1. One of the areas of great responsibility, and great controversy, for art historians, whether they are employed by an academic institution or a museum, or operate as independent scholars or experts, is that of authenticating or attributing works of art. If art historians choose to engage in the practice of authentication (stating the artwork is or is not by a particular artist) or attribution (identifying the artist), it is very important that they be aware of the issues involved.1

2. Issues of attribution and authentication differ substantially among the various fields of art history, including to name just a few, Greek pottery, Chinese bronzes and paintings, Roman copies of Greek sculpture, Indian sculpture, medieval sculpture, Mesoamerican artifacts in general, old-master paintings in particular, nineteenth-century landscape and genre works, and works of modern and contemporary art passim. In many fields there may only be one or two experts capable of giving an informed opinion. In others there may be many experts and conflicting published opinions. In modern and contemporary art, it is sometimes difficult to identify an expert at all, to the extent that artists may not have a catalogue raisonné or scholarly monograph to indicate which authors or editors would be the acknowledged experts.

3. Although many art historians continue to issue individual opinions about attribution or authenticity, due to possible risks of litigation over the rendering of opinions, these guidelines recommend a different approach. Furthermore, given the international context in which opinions are rendered, international legal issues, including those relating to ownership and libel, must be approached with caution and legal guidance.

4. “Certificate” opinions concerning or implying authentication or attribution, given for business, market-value, or tax purposes, no longer, in all circumstances, represent infallible objectivity unless they are supported by a consensus. It is recommended that art historians be very cautious about issuing such opinions solely on their own authority alone.

B. Recommended Practices

1. It is recommended that art historians render opinions only on artworks that are within their competence. In particular, it is recommended that art historians render opinions, when possible, in conjunction with a group of other scholars and conservators who can form a consensus as to the authenticity or attribution of an artwork.

2. It is recommended that art historians rely on specialists employing technologically sophisticated analytical techniques for the material analysis of objects.

3. Art-historical documentation, stylistic connoisseurship, and technical or scientific analysis, which complement each other, are the three necessary aspects of best practices for authentication and attribution. These three aspects create a consensus of evidence. A consensus of evidence is, in itself, the best approach to authentication and attribution and the best defense against litigation. In forming a consensus, the experts involved should be sensitive to the damage a publicized negative opinion can do to the reputation of an owner and the value of the art object.

4. Those asked to express an opinion on an artwork’s authenticity or attribution are advised to study the original artwork itself before rendering an opinion, although there may be instances where an opinion may be rendered on the basis of a photograph (as when the artwork is unavailable or a blatant fake). The opinion should indicate whether it is based on a study of the artwork or a photograph. In any event, relevant data, including media, dimensions, location, and mode of signature, should be obtained and carefully verified, as well as any inscriptions on the backing of the work (its verso and stretcher). The opinion should be labeled as such and should include the relevant identification data in describing the artwork, including photographic images taken from the original.

5. Art historians who face a situation that precludes establishing a consensus are advised to use caution, should consider whether to withdraw from the assignment, and/or should consult legal counsel.

6. It is recommended that an art historian employed by an institution first consult that institution to determine whether, and on what conditions or restrictions, he or she may render opinions with respect to the authenticity or attribution of works of art. It must also be determined if that institution insures the art historian with respect to such opinions. As a general rule, it is inappropriate for an art historian to render opinions on the letterhead of his or her institution without the knowledge and consent of the institution. Some institutions have devised forms and procedures for the rendering of opinions in order to minimize the risks of, or avoid, litigation. Where such insurance arrangements, forms, and procedures exist, they should be scrupulously followed. Any questions should be referred to the institution’s legal officer.

7. It is recommended that an independent art historian not render an authentication or attribution opinion absent insurance, indemnification, and a signed release of all claims by the owner of the work.

8. It is recommended that when an art historian encounters an artwork in a museum that he or she believes to be misattributed, his or her opinion should be communicated privately, not publicly, to the appropriate curator. Where the artwork is not owned or exhibited by a museum, the art historian should not get involved unless asked for an opinion.

9. It is recommended that when an art historian encounters an artwork in a commercial gallery that he or she believes to be misattributed, he or she should render an opinion only if asked to do so and is indemnified, inasmuch as it may not be possible to obtain a signed release of all claims by the owner of the work (or the gallery) once an opinion has already been rendered.

10. It is recommended that opinions be rendered for collectors only when there is a written request by the owner of the work, and that the owner provides all parties involved in rendering the opinion with a release signed by the owner and appropriate indemnification. An art historian rendering an opinion may wish to consult a lawyer regarding the elements of such a release.

11. It is recommended that an opinion on authentication or attribution not be offered unless the owner of the work provides sufficient scholarly research and technical evidence to support the opinion.

12. It is recommended that an opinion avoid commenting on the character or reputation of the seller or owner of an artwork. With respect to those cases where an art historian has reason to doubt or disagree with a proffered attribution, an opinion of “misattribution” or “not properly attributed to” is appropriate, unless it is clear that the work is a forgery. Finally, the art historian should retain for his or her own records a copy of the opinion, the release, an image of the work, and all relevant correspondence.

C. Ethical Issues

1. Although every art historian must be aware of professional responsibilities of acting on his or her expertise, there is no obligation to act individually or publicly—or to put oneself and one’s family in harm’s way.

2. It is unethical for an art historian to provide an opinion of a known fake or forgery that affirms the legitimacy of its authenticity or attribution.

3. It is unethical for an art historian to “authenticate” artworks through publicity to form public opinion.

4. It is unethical for a museum to organize or sponsor an exhibition of artworks as to which the authenticity or attribution is open to question unless the doubts are clearly indicated or the exhibition is openly devoted to assist in the determination of attributions or to presenting forgeries or misattributions.

5. In rendering an opinion, it is recommended not to charge a fee, unless circumstances would not be compromised by doing so. One exception to this recommendation would be if the artwork is authentic, published in a catalogue raisonné, and has never been questioned, and if the request is clearly for an affirmation of authentication. Other exceptions would be fees paid to technical experts such as conservators, who are part of a consensus issuing an opinion, and fees paid to authentication committees constituted by artists’ foundations or similar institutions.


The above guidelines constitute revisions of A Code of Ethics for Art Historians and Guidelines for the Professional Practice of Art History: Section VI, “Fakes and Forgeries,” and Code of Ethics: Section X, “Fakes and Forgeries.” Both parts titled “Fakes and Forgeries” have been included in Section XI, whose title has been changed to “Authentications and Attributions” from just “Attributions.”


1. These guidelines distinguish between forgeries, which are purposeful misrepresentations of an artist’s work that most often contain a fraudulent signature, and works that were not intentionally made as representations of another’s work but were mistaken for it. The former are inauthentic; the latter are most often misattributions.

Authors and Contributors

These guidelines are submitted by the Task Force on Authentication, authorized by the CAA Board of Directors in October 2008, that consisted of:

  • Barbara B. Lynes, Director, Georgia O’Keeffe Museum Research Center, and Curator, Georgia O’Keeffe Museum, Santa Fe, New Mexico
  • Francis V. O’Connor (Task Force Chair), former member of the Pollock-Krasner Authentication Board and its predecessors
  • Meg Perlman, former Director of the Pollock-Krasner House and Study Center at East Hampton, New York
  • Virginia Rutledge, attorney and member of CAA’s Committee on Intellectual Property and Chair of the New York City Bar Association’s Art Law Committee
  • Ronald D. Spencer, attorney and member of the New York City Bar Association’s Art Law Committee, counsel to the Pollock-Krasner and Andy Warhol Foundations, and author of The Expert versus the Object: Judging Fakes and False Attributions in the Visual Arts (New York: Oxford University Press, 2004)