To fix this, the projectionist puts a physical or digital (a black bar) over the top and bottom of the film strip. They "mask" the image. You only see the slice in the middle.
But , when a 4K Blu-ray is mastered, sometimes the studio is lazy. They take the Open Matte digital intermediate (the master file before the bars were added) and just slap black bars on it. open matte
Let’s do a quick science lesson. When a director shoots a movie, the camera sensor captures a massive square-ish image (usually a ratio of 1.33:1 or 1.37:1—basically, the shape of an old CRT television). To fix this, the projectionist puts a physical