The cinema crisis in the 1950's brought about the advent of the wide screen ratio. Some of them are still in use, but most are forgotten.
The most important was Cinemascope, which is still used in a modified form today. Cinemascope is based on the principle of anamorphism, by which the image is vertically compressed, either in the filming or the printing phase and then widened again in the projector by passing through a special lens. Depending on the anamorphic system used, the image obtained on the screen has a height to base ratio that varies between 1 to 2 and 1 to 2.55.
In the same years, VistaVision was used (and is revived every now and then to produce special effects). This was also a 35 mm gauge, which ran through the camera and projector horizontally. This made it possible to obtain an image that was much larger than normal and therefore with a very high quality. It was also possible to print the VistaVision gauge onto 35 mm film that ran through the projector vertically by turning the image 90o and reducing it. In this way a 22 mm x 11.89 mm rectangular image was obtained that had a height to base ratio of 1 to 1.85.