D provides products and services covering every step in the creation of photographic pictures. P, a far smaller but still prominent participant in the industry, competes with D in providing photofinishing services the conversion of exposed film into finished prints, slides, or movies. P also sold cameras as well. P does not manufacture film, but it does purchase d film for resale to its customers, and it also buys photofinishing equipment and supplies, including color print paper, from D. D has been P's competitor in some markets and its supplier in others. In 1972, D released the 110 camera and Kodacolor II film. The new camera was only compatible with Kodacolor II film, and that film could only be used with the new camera. P tried to sell a competing camera, but it was defective. P sued D claiming that every aspect of the association has been infected by D's monopoly power in the film, color print paper, and camera markets, willfully acquired, maintained, and exercised in violation of § 2 of the Sherman Act. P alleges that these violations caused it to lose sales in the camera and photofinishing markets and to pay excessive prices to D for film, color print paper, and photofinishing equipment. P argued in part that D, because of its monopoly, had a duty to disclose information about its products to competitors. The jury found for D on virtually every point. Both P and D appealed.