A monoscope tube was also sometimes used for this purpose. But they had to be custom made for a specific image. It was also only good for Black and White. ht

A monoscope tube was also sometimes used for this purpose. But they had to be custom made for a specific image. It was also only good for Black and White. https://en.wikipedia.org/wiki/Monoscope https://en.wikipedia.org/wiki/Monoscope