Why do 3D movies have blue, red and green dividends?

When shooting a stereoscopic film made by filtering technology, blue/red filters are installed in front of the left and right camera lenses, allowing only blue/red light to pass through and preventing most of the bonus/blue light. Of course, you don't have to use filters to shoot movies nowadays. In fact, some colors (such as Photoshop filters) can be eliminated by post-processing. Audiences need to wear a pair of red and blue filters when watching movies. At this time, the picture of the left projector passes through the red lens (left eye), and the red pixels removed during shooting are automatically restored, thus producing a picture with real color. When it passes through the blue lens (right eye), most of it is filtered out, leaving only a very dim picture, which is easily ignored by the human brain. On the contrary, the picture taken by the projector on the right side passes through the blue lens (right eye), and the blue pixels removed during shooting will automatically recover, resulting in a true color picture from another angle. When it passes through the red lens (left eye), most of it is filtered out, leaving only a dim picture, which is automatically filtered after the human eye transmits it to the brain. Then, after the left and right eyes transmit the images they see to the brain, the brain will automatically receive a more realistic picture and give up the blurred picture, which will be generated according to the color difference displacement.