We photographed the flow patterns of a liquid film on a large rotating substrate (650 x 830 mm). Two kinds of flow patterns were observed: turbulent-transition flow and fingering flow spread out in the radial direction. To determine the factors that affect the onset point (i.e., the "onset radius") of the fingering flow pattern, we measured the effects of viscosity of the liquid, the flow rate of the liquid from the nozzle, and the angular velocity of the substrate on the fingering flow pattern. Moreover, we devised a new equation based on dimensional analysis for predicting the onset radius of the fingering flow pattern. It was found that the predicted onset radius agreed well with the measured one; thus, it is concluded that the equation can successfully predict operating conditions of a liquid to produce a uniform film flow.