# Rear Projection Hologram



## therealjb (Oct 4, 2012)

Hi guys,

I'll just provide a brief explanation of what's going on - I'll tell you more about my theme when my story site is ready.

So for now, just think 'Umbrella Corporation' with the 'Red Queen'. Usually my queue is around 5 minutes long - and my walkthrough usually lasts around 2 minutes. This year - the plan is for the walkthrough to be more controlled with pauses and story sections meaning the time will increase to 5+ minutes.

My queue out the front therefore needs a bit of entertainment - plus some building up to the scare and an overview of the story.

I plan to have a 'rear projection screen' on the front lawn, with a creepy virtual computer interface explaining what the facility is and what the tour will showcase. This will be projected onto from the roof with my projector.



















Does anyone have any experience with something like this? I can find lots of posts about floating heads with the perspex and tv... but couldn't find anything like this.

I play on buying some film like this http://www.ebay.co.uk/itm/Wide-60-R...t=LH_DefaultDomain_0&var=&hash=item1e83fe38e1 to mount onto my clear perspex.

The idea is that I can show my 'Red Queen' as well as messages, warnings, queue times and so on.

For anyone who doesn't know what the 'Red Queen' is:









Let me know your thoughts (and please move this if it's in the wrong place!).

Jon


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## R. Lamb (Oct 11, 2011)

my first thought is that you will need to move the location of your projector. If you project from an angle like that, you will have distortion in the image. i.e. The top of the image will be in focus while the bottom will be elongated and out of focus. Then agin, that could also work to your benefit depending on the image.


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## fontgeek (Jul 24, 2006)

I would imagine that: A>your projector will need to be very bright/high lumens, B>the area behind the screen will need to be fairly dark so that it doesn't "blot out" the projected image, or C>All of the above.
Interesting film though. I'd be curious to see how it works in real life. Making an image look clear and crisp for ebay is easy, making it work in real life...
Your projector will need a strong "keystone" feature to off set the distortion from projecting at that severe of an angle.
Keep us posted.


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## fontgeek (Jul 24, 2006)

That film isn't cheap, and you'd need a good sized piece to create your illusion.
Storing it once it's adhered to the glass or acrylic will make it more cumbersome too. You'll need a protective cover for at least that side of the film if not for the whole sheet of glass or acrylic.
I would imagine that scratches and blemishes will stick out like a sore thumb.


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## corey872 (Jan 10, 2010)

Seems like a neat idea. Most projectors have a 'keystone' correction which deals with off-angle projection like you show. You'd have to experiment to see if yours does and how much it can do in order to know if the angle down from the roof will work. Distance will also be an issue. With the projector far away and people close up, pixellation of the image will become pretty apparent. You may have to move the projector much closer to get a decent image. Lastly, it would be a bit of a pain, but if you could mold the perspex into a 'person' shape, the whole thing might take on a more 3D appearance.

Good luck!


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## therealjb (Oct 4, 2012)

Wow thanks for the input!

The angle of the projector isn't really important right now - was just going for the neatness more than anything.

In previous years, the projector has sat on the ground at the bottom of the hill and projected on to the front of the house. Although I purposely went for 'wonky' and 'end of the world' kind of look.

The projector if placed on a level would only be 6 - 8 ft away from the film so shouldn't be too much of a problem with pixellation.

I would love to try and shape the display to give it that 3D effect... especially since I'll be using a family member to record the video - would be easy for a perfect 3D effect - but I'm not sure what happens to video when you play it on a non flat screen. I might give it a few tries (don't want to say it but) - I have ages until Halloween haha.

Storage would need to be taken into consideration.

Well I'll get some of the film ordered - it looks like a 4ft child sized strip will be around £40 and the perspex around the same. I'll let you know progress


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## BioHazardCustoms (Aug 5, 2009)

therealjb said:


> The angle of the projector isn't really important right now - was just going for the neatness more than anything.
> 
> - I have ages until Halloween haha.
> 
> Storage would need to be taken into consideration.


First, please allow me to say that the angle of the projector is very important. Otherwise, your image will appear distorted and off kilter, thereby ruining the effect.

Second, I'm glad to hear that someone has ages until Halloween. I feel like I am already two years behind on this year's display.

Lastly, we all have storage issues to consider, lol.


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## therealjb (Oct 4, 2012)

aha yeah, I know Halloween will be here very soon. Hopefully I'll be a bit more prepared this year though! 

I understand the placement of the projector is important - what I mean is - the plan I have/had to put the projector on the roof isn't important right now. I mean I can move it down, place just behind, or in front... kind of thing.

Yeah, storage seems to be the trickiest thing lol although with it being so thin, I'm sure it will slide in behind something.


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## BioHazardCustoms (Aug 5, 2009)

With the film being clear, I would suggest figuring out a way to project from the front, personally.


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## stagehand1975 (Feb 22, 2010)

I have seen this done with plexiglass in the past. I would imagine though that any stray light could ruin the effect as with out a white screen for the image to reflect off it could be hard to see. Also, that angle will work with the projector only if it is a projector that has capability to be adjusted for ceiling mount. This because the keystone adjustment in alot of projectors only works one way. Meaning when it sits upright on the ground. The keystone keeps the proper square image. Sitting upside down, the keystone mostly dont work backwords. To project from an elevated position like you want may may need to mount it upside down and have a projector capable of being swithed to ceiling mount/rear projection mode. Generaly found in the installation settings of the machine.


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## therealjb (Oct 4, 2012)

Yeah the projector has plenty of settings for mounting - I've had it both on the ceiling and on the ground. It has the settings - but it's an annoying menu system where you change a setting and have to wait 30 seconds or go back to the beginning lol. 

If all else fails - I'll have a white sheet screen and just project it onto that. 

I've ordered some film anyway and will post some shots of the test when I run it.

Cheers for your help


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## HomeyDaClown (Oct 3, 2009)

Maybe a simpler approach would be to use a Pepper's Ghost effect. 
This is normally done with glass or plexiglas placed at a 45 degree angle to the projection source. Thin clear plastic sheet would work the same way as long as it was stretched to eliminate any lines or wrinkles.

When this was first invented and used by early magicians in Europe, They had sheets of glass that covered a good portion of the performance stages. Actors hid in the orchestra pits and used lights or lanterns to light themselves up and appear like ghosts on the glass.


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## fontgeek (Jul 24, 2006)

If you pre-distort your image(s), you could use a curved/bent/warped piece of acrylic to project onto to get more of a 3-D effect. Pre-distorting your images to make them thinner or fatter to offset the distortion to the screen can let you have a natural looking image. You may find that projecting onto a surface like a dry-cleaner's bag will give your image more of a misty, ghost like effect, especially if you have a mild fan aimed at the bottom edge to make it ripple. This can make it look like it's a cloud of smoke or like it's a genie coming out of a lamp or bottle.


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## therealjb (Oct 4, 2012)

I just don't like the thought of a tv laid on the front lawn though, I like the Pepper's Ghost effect but I want this to be a visible projection to go with my high tech theme.

Hmm yeah, will test a few different surfaces. The film will take a few days to get here


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## HomeyDaClown (Oct 3, 2009)

therealjb said:


> I just don't like the thought of a tv laid on the front lawn though, I like the Pepper's Ghost effect but I want this to be a visible projection to go with my high tech theme.
> 
> Hmm yeah, will test a few different surfaces. The film will take a few days to get here


Don't need a TV for a Pepper's Ghost effect, just about any light source will work including a projector. One setup I saw even used an old slide projector with a slide of a standing ghost but a fog machine was used in front of the projector to distort the image and make it appear to move. doing the same with a video projector would be much more effective. Unfortunately your scene will be outside....I've also seen projectors used behind fog curtains indoors where wind is not an issue.


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## therealjb (Oct 4, 2012)

Oh really? So the projector would be laid on the floor facing the sky - and the perspex 45 degrees towards the front?

Hmm I will have to try that then - I'll see which looks more of an effect 

Yeah fog doesn't work so well in the fully 'outdoor' areas as it's an open front corner yard and the wind blows right through. I also forget how cold it is when I'm planning it each year lol.


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## fontgeek (Jul 24, 2006)

Depending upon how you light the surrounding areas, you might look at doing your projection on scrim cloth. Like a two way mirror, if the area behind the scrim is more brightly lit than the scrim is, then it shows through the scrim like it wasn't even there.
If the lights behind the scrim are dimmed, then your projected image will appear/show up on the scrim. You can get it in all kinds of densities to make it and your projected image more or less opaque.
The downside of having your projector behind the film or scrim is that the light-source itself tends to be clearly visible to the guests.


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## HomeyDaClown (Oct 3, 2009)

therealjb said:


> Oh really? So the projector would be laid on the floor facing the sky - and the perspex 45 degrees towards the front?
> 
> Hmm I will have to try that then - I'll see which looks more of an effect
> 
> Yeah fog doesn't work so well in the fully 'outdoor' areas as it's an open front corner yard and the wind blows right through. I also forget how cold it is when I'm planning it each year lol.


Or from the side like this:










The clear panel (plexi , film or whatever) is outlined in green. The front view is outlined in red with the projector would be on the left most wall aimed at the clear panel. Everything behind the clear panel is virtual / projected. This way the projector could be behind a panel or in a column hidden from view. This is also a cool way to make a head appear to float above a table.


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