All-inorganic halide perovskites hold promise for improving the thermal stability of perovskite solar cells (PSCs), but their moisture sensitivity significantly limits scalable fabrication of high-quality thin films over large areas under ambient conditions. Upscaling of uniform and pinhole-free coatings is further complicated by the fluid dynamics of the ink and its solidification mechanisms. For the first time, we demonstrate the control of film formation during ambient-air scalable fabrication of CsPbI2Br perovskite films using blade coating and investigate the coupling between the fluid dynamics and the structural evolution during film formation. As a result, we achieve power conversion efficiencies of 14.7% (aperture, 0.03 cm2) and 12.5% (aperture, 1.0 cm2), which is the highest performance for 1.0 cm2 all-inorganic PSCs. These results present important lessons on controlling the solidification of inks for the practical fabrication of perovskite photovoltaics.