The odd trial to determine the authenticity of a painting opened today in Chicago as two plaintiffs suing for $5m in damages because Peter Doig said a painting they attributed to him was not his work.

One of the things that makes the trial interesting is the previous case law where courts have ruled that authenticity cannot be determined by judge.

The New York Times describes the less-than-scintillating first day of testimony:

Mr. Doig took the stand on the first day of the trial, called as an adverse witness by the plaintiffs, whose lawyers asked him to go through the minutiae of how he creates art. The plaintiffs contend the work resembles others by Mr. Doig and employs colors he typically uses.

Mr. Doig, dressed in a light gray suit, answered politely through several hours of testimony, describing how he used projections and other tools to help create images. Most of his answers revolved around technical issues, not direct commentary on whether he had created the work.

Artist Accused of Disowning a Painting Testifies (The New York Times)