Writing Life

I’m always searching for metaphors in the specifics of science, art, sport, nature, and history that can be used to illuminate a larger human truth. In my last entry I explained how the mapping of the Earth, be it on a globe or a two-dimensional map, mirrors in certain ways the thought processes of the humans who inhabit that planet. Flat, two-dimensional maps of earth are cheaper to produce, easier to obtain, and therefore far more numerous than globes. But a good globe is far more accurate in representing the scale of landmasses and bodies of water than even the best of flat maps. Maps, therefore, might be thought of as representing information, while globes represent information that’s been put into proper perspective.

For many years I’ve been fascinated by the technology of film production. One aspect of film technology that intrigues me is the process that is often called either “greenscreen compositing” or “bluescreen compositing” but is more accurately referred to as “chroma key compositing” by those who actually employ the technique – i.e. Hollywood filmmakers and other videographers. In short, the process takes two images and combines them into a single composite image. Generally the color green or blue has been deleted from one of the images. If you want to produce film footage of a man walking along the parapet of a tall building without risking the actor’s life, chroma key compositing is the way to go. In the old days you would begin by placing a green (or blue) filter over the camera lens. Nowadays you would simply employ a digital camera that is programmed to ignore the color green (or blue). Next, you photograph the actor walking in front of a green backdrop. Because the camera cannot detect the color green, it picks up only the actor, not the backdrop. Step three is to photograph the parapet of an actual building. Then you overlay the image of the actor onto the image of the building and you get a composite image of a man walking high above the city on a building parapet. That, of course, is a brutal simplification of a very complex process, but brutal simplifications are all I can deal in. I don’t have the technical savvy to grasp all the fine points of complex processes.

For a long time it has seemed to me that there must be a great metaphor for a large human truth hidden somewhere in the chroma key compositing process. Every time I watch a film in which it is clear that a lot of greenscreen work was involved, I find myself feeling as though I am on the verge of some sort of revelation about….I don’t know – life, art, duplicity, the unseen world. For years I have been on the brink of this revelation, and yet it has never come. Thus, I have lately been reading up on chroma key compositing on the Wikipedia, and elsewhere. I hoped that after reading the Wikipedia entry for chroma key compositing, I would at long last realize what exactly it is in everyday human life that is best represented by the metaphor of the greenscreen process. But what I discovered was that the material is just too rich with metaphoric possibilities to be easily pigeonholed. Greenscreen compositing and various related photography techniques are a mother lode of raw metaphoric material.

Let us take, for instance, just one aspect of the process: the colors involved. Green and blue were selected for the process because they are not present in human flesh pigments. According to a website maintained by Boris FX, a leader in the field of photographic special effects, “human skin color is 70% red for all people regardless of race.” Wow, think about that for a moment. White people, Asians, black people, Hispanics, American Indians – we are all of us wrapped in skin that is 70% red. What a waste of time our foolish clashes over skin color seem when we consider that what we are fighting about is merely the 30% of our pigment that isn’t red. It’s often said that we are all pretty much the same under the skin. But according to a spectrometer, even our skin is all pretty much the same. Chroma key compositing, therefore, could be employed as a metaphor for race relations. But somehow this strikes me as facile. Surely there must be a more subtle life lesson buried somewhere in the mysteries of the greenscreen process. I decided to do a bit more reading.

Even though I understood very little of what I read (maybe 5%), I found my foray into the literature of videography fascinating. The many Wikipedia entries that fall under the rubric “film and video technology” are filled with poetic sounding terms: demosaicing, ordered dithering, retroflective curtain, chroma subsampling, the Schufftan process, chrominance sensitivity, luminance-sensitive elements, and so forth. Who cares about meaning when the sound is so beautiful? There is poetry in science and science in poetry. Every one of the above technological phenomena is loaded with metaphoric resonance. “Ordered dithering,” for instance, sounds like a perfect description of a day in the life of a writer (or at least in the life of this writer).

One of the fascinating things I learned about from the Wikipedia is the so-called “Bayer filter,” named after its inventor, Bryce E. Bayer of the Eastman Kodak Company. As I understand it (which is almost certainly wrong) the Bayer filter is a device that helps cameras mimic the workings of the human eye. According to the Wikipedia, “The eye’s rod cells are more numerous than cone cells and they are most sensitive to green light.” Bayer’s invention equips image-capturing devices with twice as many green pixels as red or blue pixels, allowing the camera to produce images that are similar to those captured by the human eye. As a result, green is the color most frequently used as a backdrop for chroma key compositing shots, because digital cameras dedicate more pixels to the color green than to the colors red or blue (the Bayer filter ratio is 50% green, 25% red, 25% blue). As the Wikipedia explains, “Green is currently used as a backdrop more than any other color because image sensors in digital video cameras are most sensitive to green …This mimics the human increased sensitivity to green light. Therefore the green camera channel contains the least ‘noise’ and can produce the cleanest key/matte/mask. Additionally, less light is needed to illuminate green, because of the higher sensitivity to green in image sensors.” Surely, somewhere in all this impenetrable (to me, at least) scientific jargon there lies a great metaphor for some subject larger and more important than mere moviemaking. Because the color green plays such a vital role in chroma key compositing, it seems natural to want to employ the greenscreen process as a metaphor for some aspect of environmentalism. Perhaps we could think of chroma key compositing as a symbolic representation of the blind eye man often turns towards his environment. Put a man in front of a greenscreen and photograph him via the chroma key compositing method and all you will see is the man; his environment vanishes. Isn’t that a bit like what happens when humans focus relentlessly on the material world and ignore the natural world – the latter begins to disappear? Hmmmm, that seems like a stretch even for a tree-hugger like me. It takes the beauty of greenscreen technology and turns it into a negative symbol. The greenscreen process has been a great gift to video storytellers; why employ it as a negative metaphor?

One of the most common uses of chroma key compositing is in the weather reports of nightly news broadcasts. When your weatherman appears to be standing in front of a large moving weather map, he is actually standing in front of a blank blue screen (for weather forecasting, blue screens are more common than green ones because they mimic the blue of the earth when it is viewed from a satellite camera). The camera photographing the weatherman ignores the color blue so that the weatherman appears to be standing in front of a vast void. A technician in the studio’s engineering booth lays video footage captured by a weather satellite over the image of the weatherman standing in front of the void created by the blue screen to produce a composite image of the weatherman and the satellite video footage. Because of the way this process works, you will almost never see a weatherman wearing blue. Blue ties, blue scarves, blue handkerchiefs, blue belts – all these things would appear as holes in the weatherman’s body through which the satellite footage in the background would be visible.

I have long wanted to write a cheesy paperback mystery novel called The Weatherman Wore Blue to exploit the details of bluescreen weather-broadcast compositing. Here’s my story idea: Tim and Tom are identical twins. Tim is a successful weatherman in Sacramento. Tom is a ne’er-do-well who is extremely jealous of Tim’s success. At night he practices delivering weather reports in front of his bedroom mirror. One day it occurs to Tom that, if he were to kill Tim, he (Tom) could take his place as the successful local weatherman. So one day Tom invites Tim over to his house and drugs him with a sleeping pill. Next he drags the unconscious Tim out to the garage. Tom places Tim behind the wheel of Tom’s car and then fires up the engine so that the toxic exhaust fumes concentrated in the garage will eventually kill Tim. Tom believes that when the police find Tim dead in Tom’s garage they will assume the dead man is Tom not Tim (are you following all this?) At any rate, Tom leaves Tim in the garage and rushes to the studio in a beautiful new suit to deliver the weather report in Tim’s stead. He arrives just in time to deliver that evening’s weather report. Unfortunately, he is unfamiliar with the technical details of the bluescreen process and appears on camera wearing a blue handkerchief in the pocket of his suit coat. As he delivers the weather report there appears to be a hole in his chest, through which the weather video is visible. Tim would never have made such a mistake. This error leads the police to suspect foul play and Tom is eventually found guilty of attempting to murder his twin brother (you’ll be relieved to hear that Tim woke up in the nick of time and escaped from the garage.) Perhaps I’ll change the title to A Hole Where His Heart Should Have Been. But what exactly this cheesy crime scenario has to do with illuminating a larger human truth through the metaphor of the chroma key compositing process, I do not know.

It seems that I will just have to keep pondering the chroma key compositing process until the life lesson buried therein reveals itself to me. Until then, I can at least say this much: although my cursory studies of the greenscreen process have taught me no great truths about the human condition, they have helped me to debunk one old truism, the adage about what a perfect paradise the world seems when we look at it through rose-colored glasses. In truth, if you actually did look at the world through rose-colored glasses, everything rosy in the world would disappear from it – just like the weatherman’s blue handkerchief.