The Karel Appel Foundation does not issue certificates of authenticity.

The Foundation has not processed any authenticity request for works on paper since March 2016, and in June 2017 it has ceased issuing certificates of authenticity or any other type of opinion altogether. Moreover, since recently it advises vendors not to use taglines stating that a work is registered in its archives, because such a reference may be misinterpreted as an ersatz certificate. The major auction houses have been informed by letter about this policy, which is in line with a trend among an increasing number of authentication authorities.

Requests concerning the authenticity of individual works will be referred to the catalogue of paintings, object-paintings and site-specific works by Karel Appel, which is being published in chronological reversed order on this website. Works on Paper will be included in this catalog merely in so far as they are related to paintings, object-paintings or site-specific works. The complete catalog of works on paper is an entirely different project, on which the Foundation will embark after completion of the present catalogue.

As for certificates issued before 2017, they will be examined anew within the context of the ongoing research.

Notwithstanding the above, the Karel Appel Foundation will be grateful for any information and/or high-resolution reproductions (front and back) provided when it comes to works (purportedly) by Karel Appel that appear on the market.