LIGHTING SPECIAL
brightness means for different colours; yellow might look brighter than blue at the same number. There are dozens of other approaches, and the relative inaccessibility of all that is what provokes lights to let us choose a virtual light source – HMI, tungsten and so on – and then add a virtual gel. The accuracy of that simulation varies, particularly where deep blues (like LEE Filters’ #181 Congo Blue) need that new deep-violet emitter technology, but it’s familiar. If the near future lets us do that with more confidence, nobody will object. That approach, though, encapsulates something of a recognition that LEDs will always be complicated compared to those legacy lights, which had just one switch to throw. Given the current enthusiasm for classical techniques in filmmaking, it’s no surprise we all want LEDs which combine the viceless predictability of old light bulbs with all the options of modern designs. Still, if deep blue was among the last unattained peaks of sheer capability in LED lighting, the next few years seem likely to be about control, accuracy and matching. It’s always tricky to recognise an epoch as it’s happening. LED technology in general has certainly represented one, but whether we’re about to encounter another as the field slides into maturity remains to be seen.
THE FUTURE SEEMS TO BE ABOUT control, accuracy and matching ”
CONTROLS AND MATCHING It’s rare, though, to find a modern LED that struggles to create a reasonable white. The bigger issue is finding two which create the same white. Modern LEDs are also the first movie lights that can mix colours to taste, and if we’ve picked a shade of blue-green for our moonlight, it would be great if all of our lights matched when we programme them with the same numbers. Humans are terrible at remembering what colour something is – even over minutes – but the human eye (or the camera) is exquisitely sensitive to a comparison of two lights side by side. Both are more sensitive to comparisons than a colorimeter anyone might carry around. So, matching two lights with high accuracy might take some manual adjustment – albeit from the comfort of a phone app as opposed to up a ladder with some gels.
Where things might differ is in how the controls actually work. Most people have at least seen a CIE 1931 chart and understand that it represents all visible colours. Any point on that chart represents a colour as seen by a human or (ideally, but not invariably) a camera. Set the same XY coordinates on two lights, and they should be identical in colour. Between two little-used lights employing the same underlying emitter technology from a single manufacturer, that can work fairly well. Moving a crosshair around a CIE chart by turning controls is not always intuitive. Not all lights implement it, and the alternatives may not be well standardised. Some, for instance, let users set a hue, saturation and brightness. Traditionally, zero degrees of hue means red, although there is no universal agreement on the shade of red, what 50% saturation means or what
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