Holography, that photographic technique that uses a laser to record a three-dimensional image on a photosensitive film, is, logically, an invention that came after the laser itself. Nevertheless, in 1909, decades before that kind of light existed, J. Hammond Smith published an article in the prestigious Scientific American proposing a system with six cameras that could capture three-dimensional images.
The photographs would be sent to another room, where six projectors would reconstruct the original image of the object or person. Even though it was never built, it can be considered a precursor to holography.
The Holography of 1947
It is likely that scientists began to imagine the possibility of recording or transmitting three-dimensional images even before photography was invented. Today, despite some limitations, we are able to recreate three-dimensional objects using laser beams, through a technique known as holography. Holography was invented in 1947 by Hungarian physicist Dennis Gabor, who in 1971 received the Nobel Prize in Physics for his work.
Explained quickly, a hologram is basically an advanced photographic technique that allows creating three-dimensional images using a laser to record microscopically on a photosensitive film. When this film receives a beam of light from the correct direction, it projects a three-dimensional image. Obviously, this technique, which requires the use of a laser beam was impossible to implement before its invention, which took place in 1928 when Rudolf Ladenburg reported having obtained the first evidence of the phenomenon of stimulated emission of radiation, considered until after World War II as a laboratory curiosity.
The Holographic Technique of 1909
Now, the lack of laser technology did not prevent inventors a hundred years ago from attempting to capture three-dimensional images. One of the most ingenious proposals was presented in the July 1909 issue of Scientific American. Written by J. Hammond Smith, the article explained how, using six cameras distributed around a person or object, separated by sixty degrees, it was possible to record each angle and then "recreate" it in another room.
Obviously, the system was not perfect—it did not allow "seeing" the top or bottom of the scene, but it came very close to what we now understand as a "three-dimensional image". The six images recorded by the cameras were sent to the destination site, where a group of six projectors distributed in the same way as the cameras reproduced the scene. Although it is not a "hologram" in the strict sense of the term, its purpose was basically the same.
We do not know the reasons why this technique never became a commercial product, but we cannot fail to recognize the ingenuity of its conception. As you can see, sometimes it does not take enormous amounts of resources or state-of-the-art technology to solve a problem.
