British Rothko expert David Anfam was among those called to establish whether Freedman could have believed the work to be authentic, or if her behaviour was consciously fraudulent.
De Sole bought the painting from Freedman for $8.3m in 2004 and is suing her for $25m.
Also implicated in the fraud ring are Queens-based forger Pei-Shen Qian, who has fled to China, and dealer Glafira Rosales, who has pleaded guilty to the consignment of 40 fakes. The trial is set to last four weeks.
