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“Digital-camera manufacturers are beginning to incorporate metadata. Dalsa has extended the DPX data set into its camera so that it becomes a data-gathering device in addition to an image-gathering device. The degree to which Dalsa is utilizing the header of the file that scores the picture is very commendable — they’re blazing the trail. But the system is in its infancy. “In our industry, when people see something like this happening at other companies, they don’t want to be the only ones left out, so other companies are stepping up to the plate. For instance, our next meeting will be on lenses that issue metadata from encoders inside them, and we’ll look at why that hasn’t caught on yet, why it should catch on, and how there ought to be an open standard and specification for recording that. “Every hardware company is deeply interested in the progress of the Metadata Subcommittee, and we’re doing it in the spirit of open source and accessibility — everyone can join in. One of the problems metadata has had is that it is such a technical issue that someone must get paid to solve it, and those who are capable of financing that effort want to profit from it. In the hands of a body like SMPTE, which is composed of justifiably self-interested, profit-motivated companies, it is hard to land on a ubiquitous standard, because whoever wants to do the work of building it wants to profit from it. But this defies licensing; in order for it to succeed, it needs to be open source. Rather than wait for someone to create an open-source system, I have been conducting our subcommittee meetings in the spirit that everything you say in this room becomes open source.” Advanced Imaging Systems Subcommittee “Future-oriented” has been used to describe the Advanced Imaging Systems Subcommittee. The group is home to imaging experts whose focus is on identifying and working through critical imaging issues rather than on near-term products or technologies. For instance, Advanced Imaging, in coordination with the Academy Sci-Tech Council, has been looking into the CIE 1931 two-degree Standard Colorimetric Observer — the basis for much of the trichromatic colorimetry and products in use — even though changes, if needed, would have wide ripple effects. “Advanced Imaging’s charter and intent is not focused on something having an effect in six or 12 months,” notes ASC Technology Committee Secretary David Reisner of D-Cinema Consulting. “Advanced Imaging tries to address issues that will have significant effects on how we work, whether results might be achieved soon or farther down the road. We try to take the widest view of where we should be going, what questions we should we be asking.” Advanced Imaging Chair Gary Demos of Demografx elaborates, “If, as CRTs are phased out, we find a new monitor or technology that works well, that has a very immediate effect. Advanced Imaging is driven by issues we currently face or expect to face, and we take whatever time is necessary to get results — some quicker, some slower.” As the subcommittee tackles the more complex issues of imaging, its members are able to educate themselves and the industry, even about such deceptively simple items as the correct usage of “linear” and “logarithmic.” Demos: “More than 50 percent of the attendees at the ASC Technology Committee meetings who hear anybody say the word ‘linear’ now know whether it’s being misused, and that’s a big improvement. It’s important that people understand when they are dealing with linear light and linear energy, when ‘linear’ actually means video gamma and ‘logarithmic’ can mean pure logarithmic, film density as in printing density or Status M, or quasi-log as in the Viper camera.” Reisner: “The terms ‘linear’ and ‘logarithmic’ have been used very casually. When all imaging elements came from and went to film emulsions with known characteristics and known photochemical processes, people were able to get away with it. But with hybrid and digital imaging chains, there is a lot of opportunity to come in from one direction and leave in another. That also applies to color gamut. With all these different representation issues, there is a lot of room for error. But keeping track of these issues has a big impact on the results of the DI and visual-effects processes, especially when work is being done at multiple houses.” Demos: “For basic color encoding, there was a lot of assuming about the CIE 1931 color system. We definitely have raised awareness that it contains potential weaknesses. It needs further examination, and it might not be the way to go. There was a sense that it was a panacea because so much color science is based on it. “We’ve also been flagging some things that come along, such as the fact that CRT color displays are disappearing and those are what we’ve been using as a reference that we trust. We started testing other technologies — flat panels, plasmas, various projectors and other things. We uncovered all kinds of issues there, and we also were able to strongly measure why we trust the CRT. The CRT had certain consistent properties that our measurements helped us characterize and quantify that none of the other devices seem to have or at least not have to the degree of the cathode ray tube. The CRT has many other weaknesses, but its strengths affected its use in color judgment. That was pretty significant, I thought. We’ve put a lot of emphasis on spectral radiometry.” Reisner: “In spectral radiometry, you take light and break it up into little bands by frequency, covering the whole range of human vision, and measure the strength of each band. The list of strengths of light in each band is the spectral measurement you get from a spectroradiometer. Trichromatic systems that we use very commonly in motion-picture and other imaging, like CIE 1931, use just three ‘primary’ colors of light, instead of keeping track of, say, 72 bands. Because of the structure of the human eye and visual system, light at just three colors can cause a color experience very like the full spectrum, even though that trichromatic representation is far from physical reality. Using just three color primaries, you can do a pretty good job of getting the responses you want from the eye and brain. “When you look at something that is orange in the real world, you get light at all the different frequencies. But if you look at that on a movie screen with either film or digital projection, you’re getting a highly simplified version of those frequencies — just a combination of the three primary color light sources, which may not be so simple or pure. But you can get about the same perception of color. “Different combinations of the three primaries may represent an orange that feels the same to the viewer. Two independent spectra that are perceived as the same color are called metamers. Color matching experiments looking at those issues are how the CIE 1931 Standard Colorimetric Observer and the CIE 1964 Supplementary Standard Colorimetric Observer were developed. Trichromatic systems are very practical but they are not perfect, for example different observers may perceive different colors. Gary has been one of the leading people in our industry digging into if or in what cases the known problems with the CIE systems may have an effect in creating and exhibiting motion pictures.”
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