Holograms aren't difficult. "Hologram making is a tremendous little piece of physics, but so easy to do," says Colin Davidson, a physicist who makes hologram sensors in the Department of Chemical Engineering and Biotechnology at Cambridge University. "It's exactly like developing a black and white photo, but far more realistic because it's in 3D." But how to make one? Help us, Obi-Wan...
Gather your Gear
You'll need red-sensitive holographic plates or film (you can order it from companies such as London-based Colour Holographic), a red laser pointer, developing solution, stop solution and fixing solution – all available from a photography shop. You'll also need to saw the lens off the end of the laser. "The lens focuses the beam, but we want it to be spread out to make a hologram," says Davidson.
Set up your shoot
Pick a small, shiny object such as a coin, a watch or a ring as the subject of your hologram. Get a chair and lie it on its back.
Lay a strip of glass horizontally on top of the legs of the chair and place your holographic plate on it, with the shiny object on top. The laser will point upwards from under the chair. Use a piece of cardboard that sticks out over the top of the laser as a "shutter" until you are ready to shoot.
Allow adjustment time
"If anything vibrates while you are making a hologram, everything goes wrong," Davidson explains. Draw the curtains, turn the laser on (make sure the shutter stops the light from reaching your object) and leave your setup for two hours, while the objects and the chair adjust their vibration frequencies to match. If possible, get a green bulb for the room; it will make your hologram clearer.
Shoot your hologram
After two hours of settling, move the shutter out of the way. The laser light is pointed at the object, through the holographic plate, for about 40 seconds and then blocked again. "The light goes through the plate, through the object, and reflects back and scatters all over the place," Davidson says. "When the reflected light comes back to the holographic plate, it's in the pattern you want."
Develop the image
Drop the plate into the developing solution from the photography shop. Next, dip the plate into a stop solution (or vinegar), and follow up with the fix mixture. "Now you've got the equivalent of a photographic negative," Davidson says. Shine a white light on it (a torch, your mobile phone or even the Sun) and you'll have a 3D image of your object to dazzle and amaze onlookers.
This article was originally published by WIRED UK
