The ELMO ST1200 HD PROJECTOR 2 BLADED SHUTTER UPGRADE .

[David Hardy]

I have recently here in the UK had an Elmo ST 1200HD projector converted and upgraded to that 2 bladed shutter as advertised in Steve Osborne's The Reel Image magazine . Of course this was done in order to get more light on the screen from that EFR 150 watt lamp .
I do have a question however for others who may have done the same .
Is the round glass filter in the projector lamp shroud cover supposed to be removed or left in ?
My conversion has it removed and in my experience it appears to be increasing the overall heat on the projector gate during projection .
This is not a good thing for any film as we know .
Your experiences and replies would be most welcome on this issue .

[Brian Harrington]

Good question as I've long thought about doing the upgrade on my machine. I removed that glass filter long ago, and never had any issues -- but in theory a 2 bladed shutter will not only let more light through, but more heat through as well. I'd do more empirical tests, and if you're still uncomfortable, put the filter back.

They also make the 2 bladed shutter for the ST-800 and I was considering that one more since it would be easier to do because of the simpler design.

That EFR lamp is still pretty bright, especially if you have fitted the f1.1 lens. Also, replacing the lamp socket improves the brightness quite a bit.

[David Hardy]

Thanks for your reply Brian .
I am surprised there has been not much response to my query . Maybe it has been a topic in the past and is now closed .
However i have now been able to track down another ELMO ST 1200 HD lamphouse cover with the glass heatshield intact and it should arrive with me soon .
Once it does i am going to see what if any significant difference it makes to both the light output and heat on the gate .
I have a feeling that Elmo placed that glass heatshield there for a reason .

[Paul Adsett]

I'm not very familiar with ST1200 David, but the GS1200 ( with a 200watt lamp)has a heat filter as well, but it is only in place when the film is stationary in the gate or operating at the 3 frames/sec rate. Otherwise it is pulled out of the way by a solenoid activated arm for all normal running speeds. So I think the answer to your question is that the filter is not needed for normal 18 to 24 fps operation but is needed to protect the film if the film is stopped for any reason in the gate.
I have actually upgraded my GS1200 to a 2 bladed shutter AND to a 250watt ELC lamp and film runs just fine with no damage or out of focus.

[Brian Harrington]

The ST-1200HD has that solenoid activated arm as well. The one David is talking about is plastic and is mounted on the lamp cover. I have removed mine from all my Elmos without issues. But I am running them with the stock lamps and shutters.

A 2-bladed shutter would allow a significant amount of additional heat through it. The cooling fan on the GS-1200 may or may not be stronger than the one on the ST-1200.

The reason that Elmo put it there was to protect the film from the heat during projection. Now whether or not it was an extra precaution or a necessity as a result of their tests is unknown. What we do know is that in the stock configuration, removing it is OK. I know that from about 30 years of using Elmos without it, and you will find that most people will tell you the same. I've never heard of anyone removing it who had an issue. I have even run films at 18fps with no issues. My silent dual-8 Elmos have it removed as well, and with rheostat I've slowed the film down sometimes way below 18fps. The film did not burn, but I've never done extensive tests beyond that. Those machines also have a 150 watt lamp, but an EJM instead.

But it is worth repeating that I do not know if it would be an issue with a 2-bladed shutter. Have you asked the person who did the upgrade for you?

As I said, I would do my own testing with a film that I wouldn't mind damaging. If you have a way to measure the heat at the gate, that would help, too, but even then you need to see what the effect on film is.

I'd be interested to know if the 2-bladed shutter with the heat filter installed is still brighter than with a 3-bladed shutter with it removed. It would be a shame if in the former case it is not much brighter.

[Paul Adsett]

Yes its kind of a nagging question. Elmo engineers obviously knew their stuff, and it is hard to believe that they put something in their projectors that was not required! Another possibility is that the film does not burn with the filter removed, but may bow slightly from the heat pulse from the lamp when the film shutter opens during the stationary part of the intermittent cycle. This would manifest itself as the picture being out of focus at the center compared with the edges. I have to say however that I have never seen this effect on my 2 blade GS1200 when running any color or B/W film.
Another possibility is that the filter is a UV filter, put in to eliminate film color fade from the UV radiation from the lamp.

[Brian Harrington]

I've never had focus issues with the ST-1200HD other than the "normal" focus issues where you need to re-focus slightly every now and then. I've re-run many films repeatedly over the years, and never observed any damage being done on subsequent runs.

Interesting idea about the UV radiation, but back then it doesn't seem like people were aware of fade, since it usually manifested itself a few years later. Also, sealed color films can have just as much fade as ones that were opened and projected many times.

The only other projector I have that uses the EFR lamp is my Sankyo 702, but that does not have a permanent filter in place, nor is there a place to put one in the chance the previous owner removed it. But it is a different machine, with a different fan, and different design aspects that may provide more cooling than the Elmo, but that is pure speculation on my part.

I would err on the side of caution after a 2-bladed shutter conversion, however, until I've personally done extensive testing.

On a side note, it is normal for the heat-filter glass to have a slit across its diameter. It is actually 2 separate pieces to allow for heat expansion. Many users incorrectly think it is cracked. Keep the filter nice and clean as you do your lens.

[David Hardy]

Hi Paul and Brian i actually have had that dowser removed from my machine as it was maybe just something more to go faulty in use over time . I do not need it as i always use the lamp on / off switch during projection .

[Brian Harrington]

Problem is if u stop projector but forget to turn lamp off first!

[David Hardy]

Yes and then you get a lovely burnt frame to splice out of the film .

[Brian Fretwell]

Therefore essential to keep if you are planning a conversion to HID.

[David Hardy]

Brian i still have the dowser from my Elmo ST1200 HD should i ever find the need to have it reinstalled . However i can't ever see the need for me to install an HID lamp in my Elmo within my domestic situation only these days .

[Paul Adsett]

Dave I have mixed feelings about HID. I have never seen a HID projector in action, so maybe that disqualifies me from making any statements, but this is the way I feel about it right now based on reports and opinions of HID users posting on this and other forums. First I do not really like the idea of the lamp having to be powered up for the whole time. Its not like a digital projector which you power up for a whole show, with film you have to be getting into the gate for cleaning after every few reels, and you usually have to have the cover open during threading to make sure all is ok. All that light spilling around might be a real pain. Second I have seen several posts claiming that HID lighting does not match well with color prints. The high color temp of the lamp makes projected color prints look less color saturated. On the other hand I have read that black and white prints look a whole lot better with HID lighting.
So, right now, I do not think I want to use HID for my projectors, I don't think I could tolerate losing color saturation. And my soup'd up GS1200'S ( 2-blade shutter, 250 watt ELC lamp, f1,0 lens) are really bright for my normal home screen size, although when I get out to 10ft wide scope projection, even more light would be welcome.

[Graham Sinden]

I always thought that 'split' glass David is referring to is not a heat shield as such but stops dust from the fan blowing onto the film forcing it up through the lamphouse. Whether it is really needed is another question.

Graham S

[David Hardy]

Graham Sinden that's a good point you have raised there . So still the questions remain is the split glass there in the lamphouse cover acting as a heat shield or for some other reason ? I recently noticed that my Elmo GS 800 which had been upgraded to a two bladed shutter does not have that split glass intact in the lamphouse cover . In fact i now can't recall if it was ever there at all .