LED or different lamp in 16mm projector

[Floris Vanhoof]

Did anyone succeed installing an LED or another kind of lamp in a 16mm projector?
I'm aware of the old LED topic in the archive here.
It would be wonderful if in the meanwhile anyone made a conversion that gives a brighter image to a 16mm projector.

Any kind of lamp, it doesn't need to be LED.
Lux/Lumen figures and pictures welcome!

[Marcel Birgelen]

Like indicated in that same topic, I've only ever tried it in a 35mm projector, never in a 16mm projector. The result in the 35mm projector wasn't good, but I guess that with more modern LEDs and a less ambitious screen size you can make it work for 16mm projectors. One big challenge will be getting the colors right though.

[Randy Stankey]

If you're just going to project onto a regular sized portable screen or onto the living room wall, etc., you'll probably be okay but you might have to dim the lights. In that kind of setting you'll probably dim the lights, anyway. In an auditorium with a larger screen, I'm not optimistic that you'll get enough light even if you dim the room.

With the ultra-bright LED arrays you can get, today, I'm sure you'll be able to get a reasonably bright picture but, like Marcel says, color balance might be difficult to achieve.

I suppose it depends on why you want to do this. If you are doing it as an experiment, that's one thing. If you are doing it for actual presentation, you might be disappointed.

If you are in experimentation mode, I say, go for it.

[Scott Norwood]

Are you stuck with a specific model of projector? If not, they make xenon 16mm projectors, which are suitable for quite large screens. Some tungsten models can be converted to xenon, but that is likely difficult or impossible now, since the conversion kits would be hard to find.

[Emiel de Jong]

Like Scott said, if the goal is a brighter 16mm image, a xenon projector is the way to go. Most fun however is a carbon arc machine, like the Filmoarc:
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[Floris Vanhoof]

Thanks for the replies.

It's for actual presentations.
When performing live music with my films, I play in lots of different venues:
In cinema rooms the projector can't illuminate the whole screen.
In concert venues, there's other lights (bar, safety,...) that can't be switched off.
Last week, a technician spend the better part of the day with theater curtains to get the screen small enough.


I'm stuck with my B&H TQ3 projector as it's modified for performances.
(see https://vimeo.com/393912752 if you're interested in the brainwave feedback performance)

I'd love to stick with this projector and maybe an external lamp module and extra cooling fan.
The projector need to be very portable for touring.
I took trains, metro's and planes with this projector in a Pelican case.

Any (old or new) info on conversion kits would be very welcome.

[Emiel de Jong]

Almost 20 years ago I experimented with Philips UHP "beamer" lamps in a 35mm projector: lots of light, small lamp and small switching power supply. Easy to install (with a 35mm size gate...), even illumination on the screen, but wrong colors. But maybe for your performances you can work around the colors: and then I guess it should be possible to use beamer technology, an amazing amount of light out of a very small box. The big question is: which lamp, and what condensor lens or whatever you need to get all that light through the 16mm gate into the projection lens...

[Leo Enticknap]

These guys sell an LED retrofit kit for magic lanterns. With some imagination, it might be possible to get it into the lamphouse of a 16mm portable. As others have noted, color temperature could be an issue.

[Marcel Birgelen]

Thanks for the replies.

It's for actual presentations.
When performing live music with my films, I play in lots of different venues:
In cinema rooms the projector can't illuminate the whole screen.
In concert venues, there's other lights (bar, safety,...) that can't be switched off.
Last week, a technician spend the better part of the day with theater curtains to get the screen small enough.


I'm stuck with my B&H TQ3 projector as it's modified for performances.
(see https://vimeo.com/393912752 if you're interested in the brainwave feedback performance)

I'd love to stick with this projector and maybe an external lamp module and extra cooling fan.
The projector need to be very portable for touring.
I took trains, metro's and planes with this projector in a Pelican case.

Any (old or new) info on conversion kits would be very welcome.

You'd be lucky to find a conversion kit for this specific model. But if you want to roll this yourself you need to figure out a few things first:

- How much Watt does the current lamp have and how much more light would you want to be able to get out of it?
- A LED should be about 4 to 6 times more efficient than any halogen or mercury based lamp. This way, you should be able to figure out the ballpark of wattage you need.
- Keep in mind that colors will look different with a LED light source, it's up to you if that's within the realm of the acceptable. If you use this in live-venues, colors will obviously also be impacted by other factors. But ideally, you'd be looking at a LED with a 6500K color temperature.
- You will need a condenser lens that fits your LED, this condenser LENS should at least cover the entire LED array and its focal point should be on the gate. You need to look for a lens that fits within the constrains of the current lamphouse of your projector.
- In some cases, if the focus of the gate and that of the back of your LED array are close, you will need some kind of diffuser-array in front of your LED, otherwise you risk getting the light pattern of the LED array on screen.
- All LEDs with considerable light output need proper cooling, at the very least a cooling block, but in many cases, mechanical cooling is unavoidable.

[Stefan Scholz]

We have to keep in mind, lighting a film projector gate is a very inefficient matter. The smaller the gate window, lesser light efficient it gets. The key point in projection is density of the light source, the smaller the source, the better the overall efficiency.
Lets face it, for 35 mm the effect is following using Hi Intensity carbon arc:
Loss Loss factor Remaining stream of light
Reflector effect 20 % 0.8 80 %

Unwanted reflection
and absorption 10 % 0.9 72%

Shadow in lamph. 10% 0.9 64%

Shutter 50% 0.5 32%

Gate (fullframe) 60% 0.4 12.96%

Reflection and
absorption by lens 15% 0.85 11.02 %

by portglass 10% 0.9 9.91 %

So only around 9 to 10% of the initial light travel towards the screen.

For incandescant bulbs (Mazda projection) this even gets worse, only 3% reach the screen.

So for narrow gage projection the figure are worse due to the small gate, and we need measures to counteract to get brightness. One is, using a higher density light source, short arc (Xenon, metal halide) will give 15% more light towards the screen. So it helps a little.
With LED the problem is, a fairly large source, never pin point, so efficiency worse or equal to Mazda projection to be expected.

How to achieve better light output. Let us look, where the losses are.
With a maltese cross, there is a 50% dark pattern of an image cycle. So going for a different film transport can assist. Claw transport or pin cylinder mechanisms (Lytax) like in Norelco, Polish, Sovjet or some Eikis, are a great help. With 16 mm you must start with extremely short transportation time, and in result large opening angles of the shutter. Preferred would be a single bladed, dual speed shutter, or counterotating half shutters, that minimize the cutout and opening time.
The other large loss factor is the gate. Matching the required image window as close as possible without overshooting helps. (This is why 70 mm without beam spreaders or specific "70 mm" reflectors offering an oval shaped pattern can't really work, you loose all light gain the format offers by defococusing a 35 mm lamp)
Furthermore we need a pin point light source, which, as mentioned, is a short arc lamp. For color renditioning reasons metal halide or mercury super high pressure can be a problem, as with metal halide and rare earth burners, not all spectral colors are emitted from the same location of the arc, which would require very special reflector designs. With mercury super high pressure, the Hg lines in blue and green need to be surpressed to get a white impression, as well as all UV to be filtered out, otherwise color film will suffer after a few runs.
Complicated, and not really practical.
We can use Xenon bulbs, but small bulbs below 1.5 kW are rather ineffectice, and larger ones have a fairly large arc dimension. 2 to 2.5 kW is a good compromise, which could work.
The reflector must be matched to the projector gate, which eventually requires a special design reflector and collecting gate lense.

A true life example was a large venue "movie palace" version of a Norelco (Kinotone) 16 mm projector I was offered. This was able to light a 21 ft tall screen with standardized brightness.
A pin cylinder movement was used, combined with dual speed single blade shutter. A 2 kW lamphouse utilizing a specially matched coldlight mirror and an anti reflex coated gate condensor was used. As a projection lens a multicoated special F 1.0 version was used.
The problem that turned out during the first shows, all 16 mm prints were burned, with heat bubbles.
The design offered an open sector of > 80%, and all components were engineered for highest output. They had to add 3 interference heat filters and pressurized film cooling from both sides. Still the concentrated UV of the Xenon lamp was high enough to visibly bleach out the illuminated film in the gate after a few runs.

Final conclusion?

16 mm is not a format for large screens, not from the resolution and sound quality, nor the practicability of large screen projectors. This should be done by blow up printing to 35 mm.
LED light could not be really effective, the radiating area of the cob chip is too large for efficient use in projection optics.

[Marcel Birgelen]

You can always just scan the film and use a digital projector to fake it. But yeah, the REAL thing obviously gives a lot of authenticity to it.

I agree with Stefan, 16mm isn't a format for big screens. It's very hard to get enough light through it and many 16mm projectors lack the stability needed for a proper presentation on such a screen. But a 16 to 35mm blowup in this day and age is prohibitively expensive for most independent artists. The 16mm format is interesting, because you can do a lot with it with just a shoestring business, as the entire process from start to end is still pretty affordable, as long as the 16mm film supply lasts.

As for LED's efficiency in projection optics: I think it could be done with custom optics. There are some DLP projectors out there, using LEDs with custom arrays and optics that have a respectable light output. None of them would light up a decent cinema screen, but neither will a Bell & Howell TQ3.

[Floris Vanhoof]

Thanks for these clarifying replies.

I will keep shooting and projecting on 16mm. 35 is out of reach and not portable enough.

Years ago, a technician pointed me to affordable Xenon lamps from cars.
Would any of these work inside a 16mm film projector?
A camera repair tech suggested using a lamp that works directly on 230V, so an extra (heavy) transfo is not needed.

Any ideas about this?


Edit:
Just been reading about HID 150 Xenpow lamps (6500K) + ballast conversions

here and here

do I understand correct this could be the best solution for my 16mm projector?

[Emiel de Jong]

Very interesting that Xenpow HID 150 lamp, never heard of it before. As the discussion goes on the forums you linked to, it sounds like it works well and the conversion is pretty simple. I would try it...

[Lindsay Morris]

Floris, IF you can find a TQ3 that is fitted with the Gemini lamp then you will be able to push the image to at least 7M wide. The Gemini lamp is a mercury discharge tube and are quite bright but supplies of them are getter harder to find as I believe that GEC and others who made them have long since ceased to make any more.
Another projector option is to find a ELMO 16CL Xenon which has a 250W Xenon lamp and they will also do images to 7M quite comfortably.

In the past when I had an outdoor cinema I had installed a 16mm B&H 666 which used the Marc 300 lamp which was the forerunner to the Gemini lamp and to supplement my 35mm screenings I would often use the 666 to screen local 16mm documentaries and that was doing 16mmm to 7m wide on a 10M wide scope screen OUTDOORS. Quite bright and clear and the Gemini lamp was said to be slightly brighter due to its smaller size with both lamps rated at 300W.

Since then for my home cinema I use a Harmour & Heath 16mm machine which is Australian made and uses a Maltese cross intermittent. Big heavy best and originally was fitted with a 115V 1000 watt lamp and was better as a radiator than a good light source. When the 115V transformer went AWOL I removed the 1000 watt lamp assembly & installed in its place a car headlight xenon lamp which runs from 12V DC with its own inbuilt igniter. Generally available on eBay but getter scarcer. Is supposed to be 100W but does not draw 100W from the 12V supply at only 6A (72W). In the Harmour & Heath lamp house it wwasas easy to replace the old lamp with the car headlight xenon lamp as it had a small rear mirror and the usual condenser lens behind the gate so I just had to make a bracket that held the odd style of automatic base in place of where the original 1000 watt lamp was and the filament was lined up the centre of the xenon tube where it was and it is quite reasonable light...nice and white and I have a image almost 4m wide and better than a TQ3 can produce.
An acquaintance has a Kinton 35mm machine and he bought a 200W car xenon lamp and once he worked out how to get the xenon lamp in the precise "sweet" spot to give the most light he has a 7M wide 35mm image on his screen and again that lamp does not draw 200W from the 12V DC supply ...I believe about 12A DC so how they can call the lamp a 200W unit escapes me.

On the TQ3 you might be able to cut off the ceramic holder from the glass mirror of an old ELC lamp and as the 100W xenon car headlamps are quit small I think it would go through the hole in the centre of the mirror and with a. suitable bracket get it centred on the "sweet" spot and get good screen light.
Have an outboard 12V DC supply near the machine. The existing projector fan is more that enough to keep the xenon lamp cool as in a car headlamp there is NO forced cooling.

One of those old B&H carbon arc lamp machines would be even better IF you can now source carbons.

Lindsay

[Vern Dias]

I believe about 12A DC so how they can call the lamp a 200W unit escapes me.

That's probably because no automotive system actually runs at 12 volts with the engine running. More likely runs at the 13 to 14 volts required to charge the vehicle battery.