(Above) A before and after VFX comparison from Netflix’s Bird Box (2018), which finds Sandra Bullock and two children traversing river rapids blindfolded. The movie is set in a creature-ridden post-apocalyptic nightmare where even a glimpse of the outside world results in almost instant death. The practical portions of the aquatic action were shot on location on the Smith River in Northern California. The water tank work was completed over the last two days of principle photography in a tank surrounded by 200′ of blue screen, with 300,000 gallons of water tinted to match the color of the Smith River.
The pics above come from the awesome site Art of VFX, which detailed the making of Bird Box via an interview with VFX Supervisor Marcus Taormina.