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Adding Another Dimension to Lighting


We were always going to have to spend our way out of this financial crisis, but I'll bet none of you thought it would be spent on even more large-screen television sets and on doubling the capacity of our production facilities. Although some of us are still producing HD content by upsampling SD 16:9 ma-terial before sending it out via DTV transmission gear that still bears its delivery tags, we've just found out that 3D is coming. Nobody seems exactly sure why, but it's coming anyway.

What does adding yet another dimension mean to us in the image creation business? In the very first instance it means a substantial increase in the complexity of our video chains. Stereoscopy involves creating, capturing, transporting, routing, storing, and displaying exactly twice as much image in-formation. But at the camera head, and in the processing and effects realm, things get much more complicated and will cost a lot of R&D to solve for live image making.

When we went from black and white to color television, a transition that I took part in (not in the U.S., I'm not that old), the craft of picture making changed profoundly for us. Much more than simply adding color to our existing pictures, the change involved a complete rethink of the elements of composition and pic-ture balance.

Where formerly we had exclusively used contrast, sheen and texture to separate and differentiate elements of the image, much of this differentiation was now present in the colors of the image and thus looked quite incongruous when lit in the previous style. We noticed that our backlight levels tumbled dramati-cally when the sheen of backlight on the talent's hair was no longer the only way of distinguishing them from the background.

A strange problem that arose during the transition to making color images was an obsession with color for its own sake. I have often thought of this as the era of "coloring-in television"—a time when scenery and costume designers (and sadly a few lighting directors too), vied with each other to see who could get the most colors in a single image.

I believe that the transition to stereoscopy/3D will bring us similar challenges. As we've seen since the earliest "3D creature" movies appeared in the middle of last century, designers, directors, and especially producers, have wanted to draw our attention to the depth of the image by having spears, footballs, guns and busty young women, thrusting out of the screen towards us. I am terrified at the thought of the havoc that will be wrought upon us by way of stereoscopic image generation systems. I'm concerned that we will spend years involuntarily ducking to avoid the captions, logos, station IDs, avatars and products that will come flying out of the screen towards us, until it eventually dawns on designers that perhaps subtle is clever after all.

THE FORCE OF 3D

The impact of stereoscopy on us, as the makers of television pictures, is set be profound. The photographic arts, particularly ours, have been obsessed with the business of mapping the three-dimensional universe into our two-dimensional medium—until now. So much of what we have been aiming for in our light-ing and composition has been about compensating for the absence of that third spatial dimension. Indeed, the three-point lighting process that's long been preached as the core of television lighting practice is founded on that assumption. So where do we go from here as stereoscopic imaging is hurriedly thrust upon us for making commercials, station IDs and ever-more-mindless reality shows? (Think something like "Funkiest Invasive Medical Procedures—in Gorious 3D!").

Before we dive headfirst into a paradigm shift, let's think about what additional information a stereoscopic image will contain. The whole point of the move from a single image shared by both eyes to a separate image for each eye is binocular disparity: the process that allows the brain to extract depth information from the differences between the images.

Because our eyes are only about two and a half to three inches apart, the differences between the images ceases to be significant when objects are more than about 30 feet from us. Beyond that distance our brain begins to rely on other visual cues, such as relative movement, objects obscuring each other, the fading of color, and the diminution of detail, to perceive depth, just as it has always had to do on the two-dimensional television screen.

The implication of the close-in only effect of stereo imaging is that we will have to take full account of it at the studio level of production for our talking heads in news, drama, hosting, talk shows, game shows and musical entertainment, but can safely ignore its impact on the major wide shot elements of sports and events.

DILEMMAS OF STEREOSCOPY

Will we even bother putting stereo cameras in locations such as golf fairways, arena lighting towers or blimps and helicopters, if the camera's two imaging elements will be returning identical pictures? Perhaps our producers and sponsors will be sufficiently insistent on "real 3D" that we will be forced to pull the old trick of increasing the distance between the imaging elements to get some extra depth effect. That's what Hollywood has been doing all along to make its 3D spectaculars more spectacular. It's very straightforward in the world of computer generated images to dial-up the amount of depth that the production team thinks will wow an audience.

However, down on the studio floor and on the ground we have some interesting dilemmas to wrestle with as stereoscopy comes to our world. Will the need for the keylight, our traditional source of depth information via shadows, wither and die as we are further pressured to hide the effects of age and gravity on the vain members of the on-camera professions? Will we still want as much side light and backlight to separate our three-dimensional foreground elements (talent?) from the rest of the picture? Will we be able to use less light in "dark" scenes if there are other ways to see more of what is happening?

Having already worked through the transitions to color pictures, solid-state imaging chips, widescreens and most recently high-definition imaging, I look forward with both apprehension and joy to the unforeseeable changes that stereoscopy will bring to our world.

Andy Ciddor has been involved in lighting for more than three decades as a practitioner, teacher and writer. You can reach him via e-mail c/o TV Technology.