A vintage Bell and Howell Filmosound 1540 16mm Projector

The Bell and Howell Filmosound 1540 16mm Projector and similar models were almost ubiquitous in schools, colleges and universities in the 1970s and 80s. I show you the one I have. The one innovation that sets projectors from that period apart from the  previous decades: a projection light bulb with a dichroic reflector  which reflects visible light but is transparent to infra-red radiation  keeping the film cooler. Although filters like this were nothing new in optics at the time, they only seemed to come in widespread use in the 70s along with halogen bulbs.