A Pepper's Ghost is theatrical illusion that was originally developed in the 19th century to make it appear as if real life ghosts were on stage with the actors. It has since been used time and again to delight and intrigue viewers. Most notably is the use of Pepper's Ghosts in the Disney Haunted Mansion ride.
In this tutorial, I will show you how to set up a Pepper's Ghost in a rather confined space.
1 Roll Gaffers Tape
1 C-Stand (I rented mine from a movie production rental house)
1 large mirror
1 piece of Lexan or Plexi Glass larger than your opening (smaller sizes can be purchased from home depot or lowes, but for larger sizes it is cheaper to goto a plastics company)
1 Large piece of white paper
1 Large piece of black cloth
1 Wood Clamp
Curtains or Artificial Spider Webs
1 piece of 1X2 8' long (or however tall your piece of plexi is)
Step 1: The Basics
After tons of research on instructables and other sites and even in that long forgotten medium: books, I discovered that there were three basic approaches in how to produce this illusion. Before we look into the options, however, let us first look at the illusion and how it is produced. In it's most basic sense, the Pepper's Ghost can be broken down into three elements. The first element is the subject. The subject can be many things, but it is what will form the content of your illusion. Whether it is an actor offstage or in this case, a projection, it will ultimately be the focal point of the illusion. The second element is the picture plane. This is the heart of the illusion. The picture plane serves a dual function in that not only does it reflect the image of the out of view subject, but it also is transparent so that the viewer can see the "set" beyond. The third and final element is the viewer. Without a viewer, well...this would be a bit of a waste :)
There are three basic ways to organize these elements. The Subject being above (which is easiest with a projector), the subject below (most common in theatrical use), or the subject to either side. I chose to use the side since it required the least amount of construction and rigging and seemed to work best for my space. It is important that you choose the right method for you.
Now my first problem was that I knew this was going in my office (I wanted it indoors to protect it from the elements but also to keep sticky curious little fingers off the plexi) but my office is relatively small for this kind of illusion.
So my first step was to measure and draw up my office. I am an architect so this is my approach...there are probably many ways, but this is the easiest for me. If you are not in the design field, a good shortcut is to get some graph paper, and assign a measurement to each square. For instance, on the page, every square would be equal to 1 foot...then you can draw a proportionally accurate layout of your space...to scale.
The above line drawing shows my office and the layout for my illusion.
Step 2: Standing Up the Plexi
Let me explain the progression of the image and then I will explain the construction.
My theory on how to do this in a confined space was that I needed to bounce the image at least once in order to get the size up to real life size. Sure one could buy a short throw projector, but I actually borrowed the projector and frankly, my wife puts me on an allowance every Halloween and so spending a grand or two on a projector probably isn't going to fly.
So If you look at my drawing you can see that the projector shoots the image, which passes through the plexiglass, hits the mirror, passes through the plexi again, and is projected upon the surface of the wall behind the projector. My projector sat on the ground and was angled up slightly so that there would be no interference. You could also position your projector to the side but then you run the risk of the viewers being able to see "how the sausage is made"
Ok...so now that the theory is done, let's get physical.
The first and most important item is the plexiglass. This can be glass as well or as some have talked about, window weather proofing. I actually purchased some of the 3M stuff but couldn't figure out a way to accomplish what I needed to do without building a lot of extra framework. Glass came to about 7 bucks a square foot at the cheapest, which was expensive, plus I didn't want to run the risk of shattering the huge panel I needed (4' X 8').
When deciding on the size of your panel, remember that getting it to the size of your opening is not enough. If you are going to be angling it up or down, it needs to be taller than your opening, or if you are doing it as I did, side to side, then you need to get a panel wider than your opening. My window was 6' tall by 3' wide so I bought a 4' x 8'.
Now...assuming you have procured your items, then it's time to get to work.
I started by trying to stand the plexiglass up. Obviously, this was not going to work on its own as a piece this size has a tendency to bow. I took a piece of 1x2 I had left over from another project and ran it through my table saw at a depth of about 1/2" using a 1/4" dado blade. Now this may be greek to a lot of you, but what I did was put a groove the entire length of the piece of the wood 1/2" with a width of 1/4" I then slid the plexiglass into the slot I create and now I had made a frame for one edge of the plexi.
I positioned this support piece as close to the window frame as possibly since it will be visible to the ToTs. I did not, however, try to disguise it as I figured they would be too distracted by the illusion to notice a small stick of wood running the up the edge...I was right.
Step 3: Securing the Picture Plane
I secured the wood frame at the top of the window using Gaffers tape. I cannot recommend this tape enough. It is a tape used in theatre and movie production. It is very strong, very sticky and very reliable. It won't take the paint off and it will hold. Buy it...don't substitute with painters tape or duct tape. Buy the gaffer's tape.
So now the Plexi is able to "stand" on it's own, however, it is not very well supported and it still seems like it is bowing quite a bit. Plus I think if one of my cat's came in and tapped it, the whole thing might collapse. So here I took a page out of the book of those who came before me and rented a C-Stand. A C-stand is a support armature used in photography which can extend up and out to hold something while staying out of frame. PERFECT!
Step 4: Still Securing the Plexi Glass
I positioned the C-Stand in the corner, extend it to the height I need and extend it out to hold the plexi at 45 degrees from the glass.
Step 5: In Which We Are Still Making the Plexi Stand Up
It was at this point I realized I had no means with which to attach the C-Stand to the plexi-glass. Thankfully my in-laws had just given me some wood clamps for my birthday so I attached the wood clamp to the plexi and then the C-Stand to the wood clamp. I actually "aimed" high with the C-Stand so that when I attached it, the counter weight would support the heavy plexi-glass and remove a bowing issue I was having.
Great! So now the plexi is supported and stable. It will require fine tuning but that comes later.
Step 6: Setting Up the Projector
Next, we set up our projection system.
I used an optima projector I borrowed from a local school. Schools are a great source of projectors because they all have lots of em and rarely use them. Make friends with a teacher or administrator. It's worth it.
I placed the projector on the ground. I had to stand it on it's side since my illusion was for a standing figure (Daisy from Spectral Illusions.) If you are doing something horizontal oriented, then you can just keep it flat, but angle it up a little. If your projector is on the ground, then you have to aim it up slightly.
Step 7: Multiple Images Are Bad!
In a perfect world, we all have enough room and hardware to create the kind of pepper's ghost that doesn't require shooting through the plexiglass multiple times. However, in a confined space, it becomes necessary to do just this. And as a result, there are secondary reflections that must be dealt with. I've made some diagrams that I hope will help. Forgive the sloppy nature of them...I did them very quickly.
The first image above depicts the path the light travels from projector to the projection surface. These are two of the three steps the image goes through in order to achieve the illusion.The light leaves the projector and as it leaves, because of the lens, it is expanding in all directions. First, the light comes into contact with the plexiglass. As a result of this contact, some light is reflected. This is inevitable. It is also why you see a small version of the bride projected below the window in the image in the original post. This is an artifact and is not a good thing. If this shines into the viewers field of vision, it creates bright spots and pretty much ruins the effect.The light that is not reflected continues through the plexiglass and hits the mirror. Now remember, the image is still expanding.The light then bounces off the mirror and heads to the plexiglass again (right side of the drawing). The same thing happens here as happened before, but now, the artifact is being projected backwards. This was why I had to hang the black cloth. To prevent a 12 foot tall bride from being visible at the back of the scene.Once again, the light not reflected travels through the plexi and hits the projection surface behind. Once the light hits an opaque surface, it is done expanding and this is the final image you will be using.
In the second drawing you see how the plexiglass is now being used as a mirror. The light from the projection surface is being REFLECTED in the plexiglass, not TRANSMITTED through as it has been so far. This is why the viewer can see it. It's the same principle as why, on a sunny day you can look around and see the world but the sun is a bit harder to look at. It is the difference between looking at the source of the light or looking at it's reflection.
Step 8: We're Done...or Are We?
The projector shoots an image onto a large mirror. Here the Gaffer's tape comes into play again. Love this stuff...and my wife loves that mirror...and my cats love to bat at things...GAFFERS TAPE TO THE RESCUE!!
Turn on the projector and aim it at the mirror. Look behind you to see where the image is hitting on the wall and adjust mirror and projector accordingly until it is at the height and position you would like it to be.
If the wall you are projecting onto is flat white, that is great! However, I grabbed a large piece of paper, about 36" x 96" and gaffer taped it to the wall. This provides a nice soft clean surface which will only help you in the illusion.
Now...about this time, if it is dark out, you will wipe your hands, arch your back, smile and think "AH. I'm done. This is perfection." Then you will turn around and notice that there is a giant phantom projection on the wall directly opposite the window.
Step 9: Getting Rid of the Phantom
Well it makes sense. If the plexi is able to shoot an image out the window, of course it is shooting it backwards at the same time.
I failed to take a photo of it, and I apologize for that. But on the wall at the back of the room (if you look in the drawing) I hung a large cheap piece of black felt. It was on sale a Michaels I think for like 2 bucks a yard. 3 yards was all I needed. I hung it up high enough to absorb the projected phantom, and then as an added bonus, I laid books on the shelves to create little mini shelves. I draped the fabric over these and placed artificial candles on them. This was nice because it provided a backdrop for Daisy and emphasized the fact that she was see-through.
Step 10: Tweaking and Setting the Scene
So now, all that's left to do is to carefully tweak everything. Adjust the location and angle of the projector, skootch the mirror this way and that, and most importantly, adjust the plexi. If it is bowing even slightly, your ghost will look weird. It pays to be slightly OCD on these things.
Once the image is perfect, dress your set! Remember, you are creating a play here. This isn't just some static prop with a strobe on it. This is a scene. This is theatre. And as such it needs to be properly set.
Also remember that this illusion is awesome because it works with 3 dimensions. The reflection of the projection appears to be "in" the room. Plan accordingly. The rule of thumb here is that the distance from the image to the picture plain is the sam distance the viewer perceived daise to be in the room. If you look at my diagram, you can see how she appears to be standing in front of the desk. Use this to your advantage. For more advanced techniques you can implement props "in front" of your ghost but remember you need to use custom footage at that point...that's another tutorial.
For mine, I decided to set it as a sort of seance/wedding. I used my office desk as an "altar" and put the collected writings of Chaucer on it (the biggest and oldest book I have.) I placed candles, a skull, some dead flowers and so on. These are details. And while they will go largely unnoticed, if you have your backpack and a bottle of Sunny-D sitting out, people WILL notice...so be smart about your scene.
Step 11: Protecting the Illusion
I noticed when I was outside, and you can see in the movie above, that the edge of the plexi was visible. This is where the spiderwebs came in handy. Curtains would work too, but I needed to block the viewer from seeing the edge of the picture plain.
I also recommend closing off that room. During a dry run, I got it all set up and ordered a pizza. When the delivery guy showed I was all excited to hear how freaked out he was. I opened the door, he gave me my pie, told me the score of the World Series game and left.
WTF? Why wasn't he amazed?
Oh...maybe because the cats had gotten on the computer and now I was projecting a ghost screen saver. Who would be terrified of bobbles floating around? Protect your haunt
Step 12: Back Story
Last step, give your ghost a story...it doesn't have to be anything fancy, but it makes the experience much more intense if they can put her into a reality...this was hanging just outside the window, printed at 36x48 and mounted to cardboard.
Step 13: Enjoy
Ok that's all I got.
I hope this was helpful.
It was a HUGE hit...everyone loved it and I think I've secured a place in the neighborhood Tot routes for years to come.
Please post any questions.