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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No Title/Something Black on Blue

1999
Watercolour
Misattribution
CID: 7370

Misattribution. Gouache, 1999, signed bottom right. Was offered at an auction in Tallahassee, Florida, USA. We have no reasons to believe this work was made by Constant (1920-2005). We have no idea of the current whereabouts of this work.

No Title/Pennz Oil

1980
Graphic Work
Misattribution
CID: 7371

MIsattribution. Lithograph, no year. Signed bottom right. Was offered at an online auction in Maisieres, Belgium. We have no reasons to believe this work was made by Constant (1920-2005). We have no idea of the current whereabouts of this work.

No Title/Oil Paint Thickly Applied

1960
Oil painting
Misattribution
CID: 7372

Misattribution. Oil on canvas, 1960. Signed "Constant" bottom left. We have no reasons to believe this work was made by Constant (1920-2005). The work was offered for authentication by auctionhouse in Utrecht, Netherlands. The auctionhouse was informed of our opinion of the work. In 2017 the work was shown to us for authentication by a collectioner that bought the work at the auctionhouse mentioned above.

ZT-Kop

1991
Watercolour
Forgery
CID: 8001

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 on Marktplaats by a seller from Hillergersberg, who has offered other doubtful watercolours (signed with the name Constant).

ZT-Twee koppen

1991
Watercolour
Forgery
CID: 8002

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 on Marktplaats by a seller from Hillergersberg, who has offered other doubtful watercolours (signed with the name Constant).

No Title/Abstract Yellow Blue Red

1959
Collage
Forgery
CID: 7366

Forgery. Collage, 1959. Signed and dated bottom right. We have no reasons to believe this work was made by Constant (1920-2005). Surfaced on Marktplaats. We have no idea of the current whereabouts of this work.

No Title/My Kid Can Do This (Can It Though?)

1949
Watercolour
Misattribution
CID: 7367

Misattribution. Gouache on paper, year unknown. Signed middle, right. 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. Was offered to us for authentication. Collector took the work back to the auction house after our authentication. We have no idea of the current whereabouts of this work.

No Title/Shapes

1980
Watercolour
Misattribution
CID: 7368

Misattribution, most likely a work by the French painter Christian Constant. Watercolor, no year. Signed CONSTANT bottom right. Was offered for auction at Sotheby's Paris as a Constant (1920-2005), which was written on the back of the work. After we informed them of the mistake they immediately corrected the information.

Another Pretty Bad Copy of "Interieur met laddertjes"

1960
Watercolour
Copyright Infringement
CID: 7369

Copyright Infringement. Gouache on paper, 1960, signed and dated bottom right. We have no reasons to believe this work was made by Constant (1920-2005). It was presented to us by a collectionor who bought the work at an auctionhouse in Walldorf, Germany. The work seems to be part of a series of similar works that keep resurfacing in the market, see similar entrys on this page in 2005, 2012 and three in 2016.

Owl

1969
Drawing
Misattribution
CID: 7386

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

The Umpth Copy of "Interieur met laddertjes"

1960
Watercolour
Copyright Infringement
CID: 7387

Copyright Infringement. Gouache on paper, 1960, signed and titled bottom left. We have no reasons to believe this work was made by Constant (1920-2005). A private collector send us the image. Is similar to a work of doubtful origin that was sold to an employee of a Dutch museum in 1999. In 2012 the museum offered that work to Fondation Constant for it's archives.

Copy of Vieux Clochard

1994
Watercolour
Copyright Infringement
CID: 7388

Infringement on copyrights. Gouache on paper | Le vieux clochard, 1994, titled, signed and dated top left. We have no reasons to believe this work was made by Constant (1920-2005). We have no idea of the current whereabouts of this work.