Part of Fondation Constant's mission is to protect the legacy of Constant Nieuwenhuys. The foundation is usually informed when works on the market are thought to be a copy, false or misattributed to Constant. Each situation has different implications.

  • First situation: Infringement on copyrights - an existing work of art is copied by someone, who, without prior permission of the copyright holder/Pictoright, reproduces the work and/or makes the work available to the public-with the artist’s name or his own name. This is considered a breach of or infringement on copyright and will therefore be handled by the organisation that handles the artist’s Intellectual Property rights.
  • Second situation: Misattribution - a work is mistakenly attributed to the artist. Even though there might not have been the intention to deceive, these works must be unveiled to avoid the illusion for owners or potential buyers that the work represents a certain value as if it were an authentic work from the artist.
  • Third situation: Forgery - a work of art is created with a deliberate intent to deceive. These works are usually presented falsely as a product of another time and/or artist. This could concern copies of existing works of the artist (falsification) or newly created works in the style of the artist as a consequence of which the work can be misattributed to the artist. Both situations are considered a forgery and a criminal act and will therefore be handled by the justice department and Pictoright.

The negative effects of these dealings have an impact both on individuals involved, the value of the works of the artist, and on the art market in general. Fondation Constant is supportive in the fight against these activities. We have close ties to both Pictoright, the Dutch Criminal Investigation Department for Art Related Crime and parties such as the Art Loss Register, who are all dedicated to eradicating  criminal activities from the art market.

On this page we will post information on the doubtful art works we encounter and where we have encountered them. To avoid law suits we will refrain from mentioning the specific parties involved.

NB: Fondation Constant does NOT give out certificates of authentication. When a work adheres to our guidelines for authenticity we will add it to out digital catalogue raisonné.

Tips when buying art

  • Ask for documentation on the work of art. Original works usually are obtainted through offical channels and come with invoices, catalogue/exhibition listings and are mentioned in art books.
  • Ask for a provenance. Original works are usually easily traced back to their source, this list of previous owners is called a provenance. Original works of art come with a provenance.
  • Do a background check on the seller. Is the seller a well respected art gallery that is well known for selling the art of this artist?
  • Do a google search on the prices. If the selling price seems too good to be true compared to works you find at the well renowned galleries, it probably is. However, above a certain price level most galleries do not make their prices public.
  • If a work is sold as assigned to... instead of by... it usually means there is reasonable doubt about the work's origin.
  • If buying online, check the Terms and Conditions of the online resellerThey might already indicate that they are not responsible of the authenticity of the works they offer!

These are some rules of thumb that should give you an indication of a works authenticity. If after this checklist, you still are unable to reach a conclusion, you can contact Fondation Constant for an assessment. Go to Assessment, for more information.

Fondation Constant is a not for profit organisation and your donations are always welcome and ever necessary: paypal.me/FondationConstantNL

Fondation Constant cannot be held responsible and/or liable for any damages, costs, expenses, loss or grievances incurred by publication or the use of the content published with regard to "Copyright Infringement, Misattribution and Forgery" on this website.
Fondation Constant will only publish information on such works if, after expert research with regard to the work, the case etc, Fondation Constant is of the opinion that such work is not authorised or authentic. However, these publications are to be considered the opinion of Fondation Constant only. Fondation Constant does not accept any liability for damages, costs, losses etc. arising from such publication.

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Rendition of Terre Brûlée in Yellow

1951
Oil painting
Forgery
CID: 7337

Forgery. Terre Brûlée, 1951, oil paint, signed center right. We have no reasons to believe this work was made by Constant (1920-2005).

No title/Three Figure with Bird

1949
Oil painting
Forgery
CID: 7430

Forgery. Oil painting, signed and dated top left. We have no reasons to believe this work was made by Constant (1920-2005). The work was offered on Marktplaats in the Netherlands. We have no idea of the whereabouts of the work.

No title/Two Fish

1949
Watercolour
Misattribution
CID: 8003

Misattribution. Gouache, signed Constant, bottom right, no year. We have no reasons to believe this work was made by Constant (1920-2005). The style is so divergent from Constant's work that it looks like a misattribution. The gouache was offered at an German auction and subsequently withdrawn after we informed them of the status of the work. We have no idea of the whereabouts of the work.

Copy of Femme et enfant

1997
Watercolour
Copyright Infringement
CID: 7438

Copyright Infringement. Watercolour, signed and dated bottom left. A bad copy of the watercolor Femme et enfant from 1997 surfaced on an online auction in the Netherlands in 2023. We have no reasons to believe this work was made by Constant (1920-2005). The auctionhouse will be notified. In 2024 the watercolor surfaced on an online auction in Germany which withdrew the work.

No title/Two Figures

1991
Watercolour
Forgery
CID: 8004

Forgery. Watercolour, signed and dated "Constant '91", bottom right in pencil. We have no reasons to believe this work was made by Constant (1920-2005). The work was offered at a Dutch auction house and subsequently removed after we informed them of the status of the work. We have no idea of the whereabouts of this work. 

No title-Animalistic Figures

1949
Drawing
Forgery
CID: 8005

Forgery. Drawing with crayon and ink, signed bottom left, 1949. We have no reasons to believe this work was made by Constant (1920-2005). The work was offered for authentication in 2021. We have no idea of the whereabouts of the work.

No title/Animal, Human, Bird

1950
Watercolour
Forgery
CID: 8006

Forgery. Watercolour, signed bottom left, 1950. We have no reasons to believe this work was made by Constant (1920-2005). The work was offered for authentication in 2021. We have no idea of the whereabouts of the work.

Buffalo

1969
Drawing
Misattribution
CID: 7338

Misattribution. Ink on paper, no year, signed top right. It is a work from the painter Joseph Constant (1892-1969).

No title/Creature

1966
Drawing
Misattribution
CID: 8007

Misattribution. Drawing, signed bottom left, 1950. We have no reasons to believe this work was made by Constant (1920-2005). The style is so divergent from Constant's work that it looks like a misattribution. The work was offered for authentication in 2021. We have no idea of the whereabouts of the work.

Copy of La belle noiseuse

1995
Watercolour
Copyright Infringement
CID: 7339

Copyright Infringement. Watercolor on paper, 1995, signed and titled. We have no reasons to believe this work was made by Constant (1920-2005). It is a copy of Constant's watercolor La belle noiseuse, 1990. The work was offered at an auction house in the Netherlands. After receiving our authentification the auction house took the work off their website.

Photo Constant and Boumibol

1951
Various
Copyright Infringement
CID: 7341

Copyright Infringement. We have no reasons to believe that this photo was made by Dirk de Herder, nor that it was made in 1951. We do not know whether this is an original print or a digital copy from an original photo. If at all an original print we assume it is by Bram Wisman from 1964. Fondation Constant has a similar photo by Bram Wisman in its archive. 

No Title/Bird

1948
Watercolour
Forgery
CID: 7342

Forgery. Watercolour, signed Constant '48 bottom right in pencil. We have no reasons to believe this work was made by Constant (1920-2005). The work was offered at an online auction in the Netherlands. After consulting with Fondation Constant the auctionhause withdrew the work.