A feature film was usually about 90 minutes long, but a reel of film, which was about 2000 feet long, lasted only about 20 minutes. So there were usually 5 reels to each film. As we had a feature film and a second feature, the whole show consisted of 10 reels plus one with the adverts, trailers and newsreels. The adverts, trailers and newsreels were shown between the two main films. The newsreels came in 1000 foot reels and ran for 10 minutes. If we had a long film such as a biblical epic, the whole show could be anything up to 12 reels.
Films arrived at cinemas by van in transit cases, normally on either a Wednesday or a Saturday. They were wound on bobbins in flat round tins.
Films ran from Sunday to the following Saturday. So after the last performance on Saturday nights, the films would be rewound onto their bobbins, replaced in their tins and put into transit cases. Then they would be put in a room at the back of the cinema where they would be collected by film transport during the night.
Cinema projectors were large complex machines, which had to project at a distance onto a very large screen. So they were very different from the film projectors owned by small businesses.
The projection room was above the balcony.
So as not to keep the audience waiting while one reel was unlaced from the projector and another laced up, there had to be two projectors. While one was working, the other had to be unlaced and laced up again with the next reel. The switching of one projector to the other had to appear seamless to the audience.
To save time at changeover, short reels, such as those for the adverts, interest and trailers, were generally spliced together for the run and then split up again for sending back.
There was little time for projectionists to sit back, although this did improve with later developments for loading the reels of film.
The 20 minute reel was standard for many years because the burning time of the carbon arcs in the projectors was limited.
At the Regal, there was a staff of five projectionists: Chief, Second, Third, Fourth and a trainee. The Chief and Second both had to be over 21 so that if one was off the other would be on duty. At any one time there were three projectionists on duty. Two were working while one had a break. We used to split the day into shifts, but when we were short staffed we officially did not get a break. If one or the other had a holiday we would have a relief projectionist - some of whom we welcomed, although others had their own ideas of how to run the shows and could cause problems!.
For announcements on stage and for shows and pantomimes, there was a spotlight in the projection room.
There was a switchboard for controlling the stage lighting and other electrics.
in all the cinemas where I worked, there was no automation. Although all the opening and closing the curtains and raising and lowering of the house lights were electrically driven, we had to make sure that we pressed the buttons at the right time. The aim was not want to draw the audience's attention to the fact that it was not all done 'by magic'. Many of us were proud of our showmanship.
There were quite a number of rooms that the public never saw. Apart from the projection room and the areas behind and under the stage, there was a battery room (needed because all the exit signs and exit passages had to have mains and battery lights); a rectifier room for power to the projector, arc lamps; and electrical intake rooms. The staff rooms included staff canteen which served hot and cold food, staff loos and a staff room.
The Regal was not only a cinema; it doubled as a theatre for shows and pantomimes, which not all cinemas did. It therefore also had a restaurant and dressing rooms for the actors. It was enormous. In fact it was one of the five mammoth cinemas built in Middlesex and was said to occupy the largest site of any cinema in the world.
David Daniells has also written a page on pre-digital developments in cinema projection.