U-Shaped Pattern in Picture

CAUSE: Film Defect- not enough developer in film pod. If this defect is at opposite end, it is due to improper film loading. The white tabs are caught between the film pack and camera back. See Loading the Film. On a six or two lens camera, this U-Shaped mark will appear on the left side if it is due to improper film loading. It will appear on the right side if it is defective film.