a question of time…
Article published in “Artlink, Arts in the Electronic Landscape” June 1996
Artlink covers contemporary art in Australia and through its networking with the national and international scene, provides a context for evaluation and analysis. It regularly produces Special Issues on specific areas, and undertakes major theme-based features. ISSN no 0727-1239. http://www.artlink.com.au Australian Holographics [wikipedia link]
One of the strange novelties of running a large format holography business
…is the regular telephone calls one receives from inspired and inventive people who clearly see holography as representing some kind of magical solution to often relatively ordinary problems. For example, recently a farmer from somewhere in the middle of Queensland rang me wanting to know if I could help him in creating a hologram of a large hawk to hover over his field to scare away unwanted birds.
“It must move across the field , and be able to change it’s colour and appearance totally .”
I unfortunately had to tell him that his request was somewhere on the other side of impossible to achieve. Then there was the private investigator who found his way to our remote studio location knocked on the door and asked if I could make a hologram of him to appear like he was sitting in his car when he was not actually there. I must admit this one did worry me and I confess that I actually ended up employing another private investigator to investigate him to satisfy myself that he wasn’t just pulling my leg and was not in fact visiting me for other reasons. To my amazement, it seems to have been a genuine enquiry.
These stories do illustrate the special place holography has come to occupy within the cultural psyche. Far from being feared as something foreign and unapproachable it has been embraced and almost eulogised as being synonymous with a kind of futuristic view of the world. Thanks to the script writers of films such as Star Wars and Back to the Future, the public seems to have a perception of holography that actually has more in common with cinematic special effects. Contrast this acceptance to the very slow integration of holography into either advertising, (with the exception of the ubiquitous embossed security holograms on credit cards), or the visual arts, and it is clear that Holography has probably been disadvantaged by the unrealistic publicity it has received. Somewhere between the hype associated with this new and intriguing technology, and the true nature of holography, something has become lost, and that seems to be, an understanding of the wonderful and real potential of the medium.
The principles of Holography were established in 1947, by an Hungarian electronic engineer by the name of Denis Gabor. The idea apparently arrived on Easter Sunday, while he was waiting for a game of tennis. However it wasn’t until the 1960’s with the invention of the laser that holography found the tools to give it power. So, how does it work? In essence a laser is no more than a light source, and holography, rather than being a futuristic novelty, is in fact a very close cousin of photography. Like photography, the subject is illuminated by light, and the exposure is recorded on a piece of film. After the exposure is made, the film must be bathed in developer and fixer, just like a photograph. The key difference is that holography records spatial information in a way that makes photography look woefully inadequate. A photograph of an object is somewhat like viewing that object through a pin-hole, giving a fixed perspective. A hologram on the otherhand is a truly three dimensional image, recorded on a fixed substrate,which appears to either float behind or in front of the transparent substrate, allowing the viewer to see it from a multitude of angles. A holographic master is only viewable under laser light, but when a copy is made from that holographic master, the image can become viewable under ordinary white light and in the process, the object can be ‘pushed’ through the image plane to appear to float in mid-air; a virtual image of the object, visible yet untouchable; and this is just the beginning.
Because a hologram is created by the cross referencing or superposition of light waves creating what is known as an interference pattern on the film, the recorded information is actually encoded at a resolution close to a wavelength of light, or about 2,000th of a millimetre. In other words, microscopic. When the first daguerreotypes (early photographs) were shown in Paris in the winter of 1838-39 the inventors were praised because of the amount of detail seen. Looking at one with a magnifying glass it was said, was like looking at nature through a telescope.1 With holography, it is in fact theoretically possible to put a microscope lens in front of a hologram and be able to see microscopic organisms on the surface of whatever model was the subject of the hologram. Although this degree of resolution is imperceptible, and therefore irrelevant to most applications of holography it has in part enabled the new field of holographic computer memory to be developed which will produce crystals of lithium niobate which it is theorised will allow storage capacities of a trillion bytes of data in a crystal smaller than a sugar cube.
In practical terms there are two types of lasers that produce holograms, continuous wave lasers and Pulse lasers. The analogous concepts in photography are the long exposure, and the flash bulb respectively. The continuous wave laser produces the linear beam of coloured light usually associated with the concept of a laser. This beam is split into two parts to illuminate the model and the film. The beams are then re-combined at the film plane, thereby creating the interference pattern, and the hologram is recorded. Holograms made with a continuous wave laser require the model and laser beam and optics to not move above about 5,000th of a millimetre to ensure that the superposition of the light waves forms a perfect interference pattern. This precision is achieved by the use of a vibration isolation platform on which the holographic recording environment is created. In our main studio we have a 6 x 5 metre platform weighing 25 tonnes which floats on a series of interconnected air cushions thus reducing vibrations to an absolute minimum. Using this platform, it is possible to hold flat a 2 x 1 metre piece of film and maintain it’s stability, and that of the related optics, beneath the 5,000th of a millimetre tolerance for the 4 – 8 second exposure. This procedure allows bright, white-light-viewable hologram copies of this large size to be recorded.