Looking for the "Lightroom" folder. Need to build a 4x5 slide projector

[Pirate]

I would like to build a slide projector for 4x5 chrome (slide) film. I know it can be done using something like an old Graphic 4x5 press camera, so that's covered.

What I need help on is the lighting system. I need to know what type of light to use. I can manufacture just about anything I would need to put it all together, but I need the specs on the proper light to use.

Any help is appreciated.

thanks!

 

[sevo]

What I need help on is the lighting system. I need to know what type of light to use. I can manufacture just about anything I would need to put it all together, but I need the specs on the proper light to use.

You need a condenser matching your lamp and a 4x5" image area. Unless "manufacture just about anything" includes 6" wide aspherical lenses, you'd probably be better off starting from a old 4x5 black and white enlarger, which can be had for scrap value nowadays.

 

[Pablito]

Unless you plan on projecting in an absolutely pitch black room, I'd be wary of building this from an enlarger because you'll need a much more intense light source than you'll find in enlargers. You'll have to deal with the heat from that. Also you'll have to rig up some kind of mount for the transparencies, or glass holder. Won't be fast to go from one image to the next.

If this were feasible it would have been done in the pre-digital age. Of course it's possible, but it may be more of a challenge than you anticipate.

 

[Pirate]

Yes, it may be a challenge, but I'm hoping not more than I can handle. I at least want to make the effort. This will be something for my school photo department to keep. As it is, they only have the 135 viewers and the few guys that like to expand out and shoot large format have no way to show off their work for this project of shooting slides unless they go back to 135.... which is a drag after shooting 4x5.

 

[Pablito]

Scan and project. MUCH easier.

 

[Pirate]

This is for a film class. No computers, no scanning. And I just don't want to shoot 135. There are others through the year that shoot medium and large formats also so I would be helping out those to come after me too.

 

[Phil_F_NM]

Like was said, start with a Crown or Speed Graphic. You'll need a bright 200mm or greater lens. Just get a standard 4x5 film holder and cut a hole in it for your image to be projected through.

Find an old 4x5 enlarger and use the condenser from it.

As for the light, explore LED options to keep the heat down. You're going to need to diffuse the light source then condense it. Just a piece of frosted glass would be enough to keep the details of your blub or LEDs out of your final image.

If you need even more light find a way to reduce your school's current down to 12v and use an automotive LED lamp. HID will be far too hot for projection, but many of the aftermarket LED bulb replacement lamps made for brakes or signals could put out enough light.

Take photos of the whole process and post them and your results here! Sounds like a fun project.

Phil Forrest

 

[Pirate]

Phil, I had wondered about using a car lamp. I also build guitar amplifiers so making a circuit that plugs into the wall and converts to 12V DC is not a problem. I just might explore that.

And I'll definitely document and post the project as it goes.

 

[Phil_F_NM]

Just make sure to use a cold source of light or you'll have to give the projector its own ducted air conditioner to prevent melting your film. 😀

Phil Forrest

 

[sevo]

your school's current down to 12v and use an automotive LED lamp. HID will be far too hot for projection,

If you build the projector out of a enlarger, the enlarger's lamp housing, condenser and IR filter will deal with that. Large format enlargers use 250W+ of incandescent or halogen, and commercial large format projectors have even more powerful lamps. So heat is manageable (and already managed if you start out from a enlarger). But when you switch from 250W halogen to 120W HID (which would double the light output while halving the heat output), the increase in UV will be an issue - such a conversion will need a heavy duty heat proof (i.e. glass/dichroic) UV filter.

Another thing to be aware of is that the cooling of the film in enlarger heads with a passively cooled "stovepipe" incandescent lamp housing depends on the film carrier being in the lowest/coolest point - if you alter the (vertical) orientation of the enlarger head to horizontal, you'll have to adjust the cooling system to make up for that.

 

[Roger Hicks]

Unless you plan on projecting in an absolutely pitch black room, I'd be wary of building this from an enlarger because you'll need a much more intense light source than you'll find in enlargers. You'll have to deal with the heat from that. Also you'll have to rig up some kind of mount for the transparencies, or glass holder. Won't be fast to go from one image to the next.

If this were feasible it would have been done in the pre-digital age. Of course it's possible, but it may be more of a challenge than you anticipate.

It is, and it was: I saw 4x5 inch projectors at photokina 20 or 30 years ago. They were huge -- as I recall, over 1.5 metres/5 feet long and over a metre (40 inches) in diameter -- but they existed.

Enough Googling or other research will probably winkle out the information. I'm afraid I didn't pay much attention at the time because I thought the whole idea was silly. I still do.

Edit: Noblex was the one I remember best. Linhof may also have made one, and Frances thinks she remembers one from Kindermann.

Cheers,

R.

 

[sevo]

I'm afraid I didn't pay much attention at the time because I thought the whole idea was silly. I still do.

They had been the standard when small projectors weren't feasible, and they long survived in the niche for ultra-large projection - from lecture halls to open air stages. With the advent of xenon arc and HMI lamps that allowed for blasting up to 1200W of light (the equivalent of 5000W incandescent) through a medium format slide without melting it, the high power 6x9 Goetschmann projectors took over by the eighties, but open air event and film lighting companies often still have some odd sub 4x5" large format projector somewhere in their lists.

 

[Roger Hicks]

They had been the standard when small projectors weren't feasible, and they long survived in the niche for ultra-large projection - from lecture halls to open air stages. With the advent of xenon arc and HMI lamps that allowed for blasting up to 1200W of light (the equivalent of 5000W incandescent) through a medium format slide without melting it, the high power 6x9 Goetschmann projectors took over by the eighties, but open air event and film lighting companies often still have some odd 4x5" projector somewhere in their lists.

The standard, surely, was the 'magic lantern' quarter-plate (83x108mm) format; I imagine that in continental Europe 9x12cm may have been usable in the same projectors, with different carriers, but 4x5 inch (101 x 127mm) is another matter. With lantern slides, the full image area was not usable: there was about 3mm or 1/8 inch of binding tape around each edge.

The ubiquity of the lantern slide format was why I said I thought 4x5 inch projectors were silly. Well, that, and as you pointed out, the availability of more powerful, cooler light sources to allow the use of 120-format slides instead of lantern slides.

Cheers,

R.

 

[sevo]

The standard, surely, was the 'magic lantern' quarter-plate (83x108mm) format; I imagine that in continental Europe 9x12cm may have been usable in the same projectors, with different carriers, but 4x5 inch (101 x 127mm) is another matter. With lantern slides, the full image area was not usable: there was about 3mm or 1/8 inch of binding tape around each edge.

Right. That is, as condensers are circular, the maximum (rectangular) image area inherently is square. The German lecture room projectors often were for 10cm high tape framed glass slides, with a usable area of about 9x9cm, that is, the square crop from 9x12. Or, with a spacer insert, magic lantern quarter plate, if you wanted it rectangular. I supposed (perhaps wrongly) that a corresponding 4x4" crop format exists in the metrically challenged world.

FWIW, Goetschmann built one modern (upright) 9x12cm projector in the eighties/nineties, the G912. As the name suggests, it did not fully cover 4x5". It cost a arm and a leg (and a couple of kidneys thrown in), and only a dozen or so were ever built.

 

[Roger Hicks]

Right. That is, as condensers are circular, the maximum (rectangular) image area inherently is square. The German lecture room projectors often were for 10cm high tape framed glass slides, with a usable area of about 9x9cm, that is, the square crop from 9x12. Or, with a spacer insert, magic lantern quarter plate, if you wanted it rectangular. I supposed (perhaps wrongly) that a corresponding 4x4" crop format exists in the metrically challenged world.

FWIW, Goetschmann built one modern (upright) 9x12cm projector in the eighties/nineties, the G912. As the name suggests, it did not fully cover 4x5". It cost a arm and a leg (and a couple of kidneys thrown in), and only a dozen or so were ever built.

Thanks for the information. Highlight: as far as I am aware, there never was a 4x4 inch/101x101mm format, but of course quarter-plate was 3x4 inch/76x101mm when masked.

Bear in mind too that a lot of Europe remained 'metrically challenged' for much of the 20th century, as with Leica's 39mm x 26 tpi thread. For that matter I learned a day or two ago that until the early 1980s Ducati used '7/16 Whitworth with 20 tpi', which is actually a UNF thread (assuming the correct thread angle) though not described as one. They were, therefore, both metrically and imperially challenged.

Cheers,

R.

 

[Pirate]

Thanks a bunch guys, this is all great information!

 

[larmarv916]

I would say....lets look at a LED light source...almost zero heat. Mounted behind a "ground glass" interface...space back a couple of inches. Old 4x5 camera body. You should be able to use your "shooting" lens on it original lens board....As the original shooting lens makes the best projecting lens...in most cases. or find a cheap normal on a lens board. The you would have low energy and no heat projector...diffused light similar to a old cold head enlarger. That's about as cheap as it gets.

 

[Fuchs]

Just a suggestion, but why not trying with an overhead or transparencies projector?

 

[sevo]

Just a suggestion, but why not trying with an overhead or transparencies projector?

There actually have been some with large format conversion kits (masking frames and reduced size condensers/mirrors).

 

[Pirate]

If it would give a strong enough picture, I would go for that. I think projecting a 4x5 slide film vs. a transparency with writing on it may be a little different though.