A View From Behind The Meter
Seeing The Night Sky With New Eyes
When I was working on the television series “Astronomers” as an independent gaffer, we were shooting at Mount Palomar Observatory, and interviewing a woman who had been working for fifty years recording the color spectrum of light coming from individual stars. This interview changed the way that I looked at the night sky forever. This process, that she was involved with, could capture the light spectrum on a glass slide and by examining the color values on that slide gave information on the physical makeup of that star. During the interview she mentioned that she had been doing that same job night after night for fifty two years. Against the wall near her desk was a cabinet that housed thousands of slides, each carefully marked, labeled, and categorized as interstellar bodies in our solar system.
It wasn’t until nearly the end of the interview that, with modern astronomy methods changing the way we were exploring the heavens, and our dependence on visual observances giving way to infrared capture, she realized that in all those years she had been exploring only five per cent of what was really there. In other words the sparkling starlight that we view at night represents a tiny portion of what’s really there. In fact, it only represents a five percent and the rest is a mass that does not emit or reflect light, so, in all practical purposes, this mass is invisible to the eye.
We are light chauvinist beings. By that I mean we gauge what is real and what is not real by viewing the light reflected on it. If we can’t see it, it truly doesn’t exist for us. A very clear example of what I’m speaking about is the blue sky surrounding our planet. The blue sky only shows up from our viewpoint when light from the sun strikes the particles in the atmosphere and the shorter blue or ultra violet portion of the light is scattered making the sky appear blue. At night however, without light striking these particles, the starry cosmos shows clearly and the particles are invisible. When astronomers began using infrared telescopes the mass, which made up 95% more volume, of matter appeared in their calculations. It completely changed our viewpoint of the cosmos seen in the night sky and today I cannot look into the sky without an awareness of this fact. As a topper to this, when asked; “What about here on earth?” she smiled and said the same is true for the room we were standing in. The mass surrounding us individually is much more prevalent than we had ever imagined.
The sun, which is a black body radiator, creates the light by which all life sustains itself and that light moves at an incredible rate throughout the cosmos. 186,282 miles per second to be exact, and it arrives from the sun in just eight minutes. The color temperature is 6500 degrees at noon varying at sunset and sunrise depending on the cloud filled atmosphere both at morning and evening. It is really an electromagnetic radiation generated by the suns heat signature and most of the dangerous solar winds and ultraviolet rays are reflected away from earth by our precious magnetic field. Thus the suns rays give earth the light that preserves life on the planet sans the dangerous elements contained within that light. What’s interesting about this life giving light is that we only see 44% of the spectrum or 380 nanometers to 740 nanometers. The rest is invisible. We have labeled infrared and ultraviolet light as the terms that explain this invisible part of the spectrum. Now all this visible light that is arriving in our universe comes as infinitesimally small particles called photons and these photons exhibit properties of both particles and waves. They can be reflected, refracted, and scattered. Reflected is how we view our universe (All that is real is what we see) refracted is the phenomenon of a straw entering a glass of water actually changing direction before our eyes, and scattered is what I described earlier with regards to the blue sky.
The Elements Of Light
The elements of light that most affect us as lighting technicians are intensity, color temperature, color rendition, and spectral distribution. All these elements are under our control to a greater degree and can be manipulated to alter the frames emotional response by the viewer. Intensity of light is the most familiar, for without the correct amount of light on a subject it is hard to see as both under exposed light and overexposed light is considered a negative. CCT or more commonly spoken of as Color temperature is the warm verses cool atmospheres that can be created at both ends of visible spectrum. Daylight at the high frequency end is usually considered 5600 degrees whereas interior incandescent light is dictated by the maximum heat capacity of the tungsten filament or 3200 degrees at the low frequency end. Color rendition on the other hand is whether the instrument creating the photons contains a full spectrum of color. If it does not contain a full spectrum it will not render color correctly, the color reflected off our subject by that instrument will vary slightly. Red can become too orange or to purple. CRI, or color rendition index which is what this is referred to, is becoming more important especially in the LED age. The final element that we can control is the quality. This can be demonstrated by using gel or diffusion materials to soften or altering the spectral distribution of the light. Whether we are aware of it or not these elements are what we are manipulating when we light our subject matter and our eyes, if we are careful and skillful, will give us the picture we wish to have.
Lighting Choices Bring Us Closer To The Sun
All of the fixtures we use are duplicating the light we perceive as emanating from the sun. There are basically five methods of producing light that are in use throughout the media today. The first is one we have been using for almost a hundred years and that is the incandescent or tungsten filament. This type of light began to be used in the early twenties and companies such as Mole-Richardson, Century, Bardwell-McAllister, and Strand all began manufacturing instruments for use by film-makers during this period. The second is HMI’s Hydrogyum (Mercury) – Medium Ark-Iodide which was introduced in the early eighties and have eclipsed the use of carbon arcs as the prime daylight source which match sunlight, as far as color temperature is concerned. The third is Kino-Flo or fluorescent lighting which was introduced in the late eighties as a soft source fill light with a thin small footprint. The fourth is Plasma and had been just a Tesla theory until the turn or the century and now has several manufacturers’ beginning to promote this new technology. Finally there is Light Emitting Diodes which I believe will eclipse all light creation in the future. Of all these systems the most efficient is the LEDs and at present the fixtures that have been developed are reaching an equivalent level of illumination as high as the 2500 Watt HMI systems. Mole, as well as other companies, is working to develop larger wattages such as 5,000 watt instruments and I’m sure that, in time, all wattages will be duplicated in LED format. I do believe that in that in our time LED’s will replace all light creation in the future, whether its in our homes or on our sets. When I first started in the media, as a young twenty year old, all the equipment I worked with no longer exists. The cameras, the microphones, the recording equipment, the editing machines, and even the lighting fixtures all have disappeared. New technology has altered forever the way we produce the media of today and light creation is just the next in line. The sun will always be there but how we match that light is under a massive revolution at the moment.
-Michael Rogers, Lighting Consultant and Educational Outreach