Twenty-five years ago I wrote an article for the American Society of Cinematographers Magazine, which is reproduced here as a PDF file. It’s about the lack of standards for the projection of 35mm over and under format movies. The 35mm frame, in this process, is split horizontally into two wide aspect ratio sub-frames and these have the left and right perspective views. The sub-frames are projected through optics that polarize and combine them when projected on a “silver” screen. If everything is done correctly the result is a good 3D image.
I have some experience with this format and I can tell you that it can be made to work but usually the projection was botched which is why the early 80’s effort, with films like Jaws 3D, failed. The article for the ASC Magazine talks about one of the issues that kept the process from catching hold, and subsequently I was the chair of the SMPTE working group that sought to create a standard for the process. We actually created two related standards, as you can see from the other attached document, SMPTE 257, which was first balloted in August 1990. It has been reaffirmed/revised over the years. The attached version here is the latest as reaffirmed in 2003.