How programmable are 35mm projectors?

[Alexandra Bischoff]

Hi all, new member first time poster. Please forgive my relative ignorance as I’m a definite newbie to film tech, but I figured you’d all have the best answers to my potentially simple question.

I am a multimedia artist and I’d like to create a multi-35mm-projector gallery installation that is capable of:

1) running on its own and restarting on its own; and
2) being programmed so that each slide is shown at variable intervals (ie. slide 1 for 10s, slide 2 for 20s, slide 3 for 5s, etc etc).

My main question is:

1) are there existing 35mm projectors and related equipment that can accomplish the above or will I have to hybridize analog and digital technologies (ie. introduce the use of a raspberry pi and/or simple robotics to change slides)?

I have of course encountered slide projectors that are programmable but cannot discern if they have the capacity for variable times for each slide and/or if they can restart on their own. I am also concerned with the heat of the bulb if the projector is run for hours on end, but have already begun to research ways to retrofit projectors with a LED bulb. Any advice on the latter is also appreciated.

thanks in advance!

[John Eickhof]

It sounds like you are mixing apples and oranges, the use of still 35mm slide projectors in multi media presentations, as well as sequential and non-sequential image projection has been a use of them for years and there were commercially available programmers integrators and sequencers for them on the market, this forum touches on that subject in many posts, do a search...but the main subject here is motion picture film projectors used industrially and commercially in theatres and in general they project motion pictures and are designed for continuous operation depending on the source film being projected, there were electro-mechanical automation systems that would start and end projection, operate house lights, curtains, etc., and sound / picture formats etc., and the latest were microprocessor controlled however there were film projectors made or modified for single frame, stop motion, background or effects use but the introduction of digital projection, that type of production as well as use of actual motion picture film is now a very limited process when only a decade or so ago was the standard for over 100 years, there are a few on this forum that may be able to provide better information, I hope they read your post and respond. have fun!

[Frank Cox]

You're talking about slide projectors and not cinema projectors.

Any slide projector that I've seen is a very simple mechanical mechanism where you click the next or previous button and the slide gets removed and replaced in front of the light.


If this is for an art thing you could make a Rube Goldberg style mechanical controller device using gears and relays and maybe something like marbles or a weathervane or... well, the sky's the limit really, for introducing a randomness factor. Which could look pretty cool if it's done well.

A factor you'll need to consider is fading. I used to have a slide projector that I used before the movies started to say "Welcome to the theatre" "Happy Halloween" "Merry Christmas" and had to replace the slides fairly regularly when they faded out.

[Sean McKinnon]

Some models of Kinoton Electronic projectors could be made to do as you describe but it would cost a lot to modify and setup and there is only one company i know of that would be able to rent such a machine.

[Randy Stankey]

Way back in the day, there used to be a device called "Areon" slide projector control.
It ran on audio, cassette tape and it used one of the tracks on the tape to record commands for the projector.

You could command the projector to bring the lamp up or down on a timed fade and you could advance to the next slide or move back to the last. The machine could control three projectors, simultaneously and, with careful programming, you could make an automated slide show that would run at the press of a button.

If you focused all three projectors, carefully, on the same screen, you could create a seamless multimedia show with cross-fades and everything, perfectly timed to music.

It's been a long time since I used the Areon. (I forget how to spell it.) Anyhow, I know that there were several brands of controller that could do the same thing. I'm sure you can find a controller that can do what you want, even with scheduled showtimes.

If you are handy with electronics, I'm sure that you could build a Raspberry Pi or Arduino to control your projectors. In fact, if I had the time and money, I might like to try it, myself.

[Phillip Grace]

This is very well-travelled road. Multi-Image A/V shows based on film technology developed into something of an industry in the 1980's. Everything you need already exists for productions on any scale from a basic 2-projector dissolve to a multi projector computer controlled extravaganza.
As John mentioned, a search on this site will bring up some fairly recent discussion on the subject. Also, this Wikipedia page and the links on it are a handy starting point. https://en.wikipedia.org/wiki/Multi-image.
The workhorse slide projectors are Kodak Carousel S-AV 2000 series, and Kodak Ektagraphic. The newer Kodak Ektapro series from about 5000 upwards also provide some advanced control functions onboard.
Frank's comment about image fading is worth noting. It certainly happens over a period of time, but I know for certain that an Ektapro with its hot bright EXR lamp will produce a significant change over a couple of hours of continuous exposure.

[John Eickhof]

to add to Seans post, christie was working on stepper motor intermittent projectors for Iwerks ( and Iwerks was building their own) they were very similar to the kiniton, i would suppose that could be a base for a single frame or even short motion version forward or reverse and variable speed but depending on lamp output the heat on the film would have to be addressed at slow or single frame speeds...there were several of these prototypes on epay recently...

[Pete Naples]

to add to Seans post, christie was working on stepper motor intermittent projectors for Iwerks ( and Iwerks was building their own) they were very similar to the kiniton, i would suppose that could be a base for a single frame or even short motion version forward or reverse and variable speed but depending on lamp output the heat on the film would have to be addressed at slow or single frame speeds...there were several of these prototypes on epay recently...

Having worked on those, the Christie Epic, they are best left on ebay, or preferably a skip.

[John Eickhof]

Pete, i figured they were a pos! not sure how the Iwerks version worked out...

[Mark Gulbrandsen]

Much stuff Iwerks actually built was pretty good stuff. For the 15/70 stuff they went to CDC, and those projectors were rock solid. The Linear loop projector is also pretty darn amazing... The Late Phil Hill worked for Iwerks and made a number of breakthroughs for them. His rectifier design for the 15/70's was a nice way to light up a 15kw lamp... The only decent stepper driver projector I've worked on were the RCA FR-35B's. The FR-35A's were unpredictable. I bought the FR-35B in the photos from Editel in Chicago for $500 when they decided to install a Rank scanner. Show Scan also had their stepper drive 70mm projectors that seemed to work fine. There are photos of the linear loop and the 15-70 3-D system in the F-T Warehouse.

Edit: Not only was the FR-35B stepper pull down, but it also utilized the same stepper to register each frame... It had sensors that looked at the perforations...

[Gordon McLeod]

to add to Seans post, christie was working on stepper motor intermittent projectors for Iwerks ( and Iwerks was building their own) they were very similar to the kiniton, i would suppose that could be a base for a single frame or even short motion version forward or reverse and variable speed but depending on lamp output the heat on the film would have to be addressed at slow or single frame speeds...there were several of these prototypes on epay recently...

CFS did build a servo motor drive projector called the Dreamcatcher MagnaTech made studio electronic machines as did Westrex. Even EPRAD got the first patent for a electronic drive intermitent

[Mark Gulbrandsen]

The CFS should have been called the "Nightmarecatcher", and let us not forget their 15/70 projector which was an absolute disaster. Interestingly, CFS also built the 15/70 lamphouses for Cinema Developments 15/70 machines. Outside it looked like an Imax lamphouse, but inside it was extremely well built, more like a tank. Photos of it in the warehouse...

[Gordon McLeod]

actually the dreamcatcher was a excellent concept machine and overall most worked well The Maverick was not a CFS product but a venture of World Odyssey Ultra-70

[John Eickhof]

I have an indexing movement that Dick Niccum gave me from the CFS version, very interesting unit!

[Mark Gulbrandsen]

actually the dreamcatcher was a excellent concept machine and overall most worked well The Maverick was not a CFS product but a venture of World Odyssey Ultra-70

There were no Dreamcatchers at any Post Houses or screening rooms I ever serviced. They all had Magnatech's, or the RCA's, or older standard projectors.
Luckily only one Maverick was ever sold, and it did not stay installed very long. Pretty sure it was replaced by an 8/70.