Meeting - May 31, 2012

May 31 2012

The Hollywood Section meeting held a second meeting for the month at the AMPAS Pickford Center Linwood Dunn Theater on May 31st, 2012, this time, entitled “Digital Imaging with LEDs, More (or Less) than Meets the Eye”, in part, as a review of the fundamentals of white light created from LED sources, including trichromatic and pumped phosphor systems.

The meeting was also purposed to explore spectral power distribution, and some of the observable and measurable effects of non-continuous and continuous spectral power on motion picture and television imaging systems, particularly with regard to white light, and traditional relative to light source measurement determinants such as CCT (Correlated Color temperature, the absolute temperature of a blackbody whose chromaticity most nearly resembles that of the light source), and CRI (Color Rendering Index, a measure of the quality of color light).

Hollywood Section Chair Eric Gsell began the evening by welcoming an audience of over 180 people, the majority of whom raised their hand as non-members, and were attending a SMPTE meeting perhaps for the first time, as interested industry guests.  The meeting had been publicized, as had the last several chapter meetings, by the American Society of Cinematographers (ASC).  

Bill Hogan introduced the first speaker, Jon Erland, who provided a summary of color and its perception, and who gave his own personal perspective of the essence of a viable color imaging system.

Jon opined that for a system to be considered a viable system, it is to provide and help assure a basis for


predictability, and that it was of the best long term intentions that color motion picture film, introduced in 1951, still dependent based on scene light, exposure, developing, and printing with stock and corrective filter biases, like modern color television cameras, are both the essence of fundamentally predictable systems because they were designed for exposures based on continuous spectrum white light.

It was the behavior of the tungsten filament illuminant as used primarily for interior photography that was determined to emit or reflect the best continuous spectrum for predictably exposing normal current color motion picture emulsions for color and tonal representation, or as its spectral power is detected in fundamentally quantum linear colorimetric photo site CMOS, and CCD sensors.

Mr. Erland pointed out that when spectral power of a light source is non-continuous, the fundamentally predictable systems are forced to render what can become unpredictable results.  On the other hand, when a solid state or Light Emitting Diode (LED) light source is designed to be predictable or when it can be modeled when adjusted and measured appropriately, new efficiencies in lighting can be unleashed.

Three years ago, these observations had come to the attention of the Academy of Motion Picture Arts and Science Technology Council from user reports on certain use of solid state and Light Emitting Diode (LED) lights, and they resulted in the formation of a Solid State Lighting Subcommittee, of which Mr. Erland is the current Chair. 


Ryan Fletcher, with ARRI, in
conjunction with Mr. Erland’s opening live and filmed presentation, showed software-based Matlab-style plot and digital chart color patch examples of the modeling tests and ongoing analysis undertaken in
research by the Academy to observe and measure the phenomenon.

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--Chris Bone, reporting Section Secretary/Treasurer 2012-2013