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July 2017

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Page 32 of 43 31 POST JULY 2017 consumer market at this moment may be the driving incentive to high dynam- ic range production, where the creative people who make content feel the need to respond assertively to the new oppor- tunities for expression. The creative forces have to regard the increase in resolution, contrast and color, as the essential three categories of image improvement that dif- ferentiates their creative efforts from their competition, for that which may be now or may be soon available to their viewers. The actual results the viewers may see may be different depending on whether the viewer sees the content in a cine- ma, and then, what cinema version they see, and what home version they see, or how they view it or what they view it on. There is also a call for changing standard dynamic grading practices to allow for brighter images and increased contrast. The idea of a 300 nit aim luminance is to more closely match the actual conditions under which people tend to be viewing and the brighter displays they tend to be viewing their content on. UNFINISHED STORIES The problem is that the stories on stan- dard dynamic range and high dynamic range are not finished, nor is the story on the full amount of useable color, nor what the resolution needs to be to appear impactful or convincing. When Ultra High Definition first came out in 2013, the first deliverables were 8 bit BT.709 color, with little resemblance to the refinements brought out by 10 and 12 bit wider DCI-P3 color and extending beyond into BT.2020 color and high dynamic range. There is new talk, also, about creating some subtle adjustments in grading, based on high dynamic range deliverables seen in a dark room, versus a bright room, when viewing. We are told that for the time being, you might want to preserve all the image data you can for later rework, stay in RGB image data form (or learn to double check your conversions so luminance doesn't get tone mapped — stretched or skewed — during conversions to or from YCbCr between different color spaces). You may want to move to 16-bit half float, such as in OpenEXR, to preserve differences in DCI-P3 that can't be encapsulated fully in BT.2020, and to expect to work toward 75 percent saturation goals in calibrating BT.2020 on reference displays and work patch sizes around average picture level display limitations for higher calibration accuracy. And, there are probably more things to consider doing, technically, so your high dynamic range work can be created and represented more accurately as to being closer to your artistic intent. KEEPING POST BUSY The good news is that this continual evolution can keep the production and post community busy working out their story telling processes to be able to cover the assorted varieties of the new- est deliverables. The challenges of the times can bring the artistic community together to help qualify or simplify some of the important decision processes as to what deliverables are to become the most relevant investments of their best efforts. If one is compelled to produce different high dynamic range versions of their content, such as an HLG high dynamic range version, a DolbyVision (with DolbyVision active metadata) ver- sion, an HDR10 (with static metadata) verison, an HDR10+ (with active metada- ta) version, there are associated costs to directing all the changes in grading. The results need to be creatively acceptable to some degree in each version. The "Hollywood" creative answer to high dynamic range and extended color may turn out to be, to make the best effort deliverable based on using the best distribution format available for the theater, and let everything else be driven from that, possibly meaning up slightly in extended highlights for high dynamic range home viewing. Digital cinema, as an art form, is not standing still with regard to technical changes. Changes are coming from blue laser or RGB laser projection technologies, large light emitted panel as- semblies and from potential plans to raise brightness by a factor of two or three times what is being seen now for standard theater viewing. There is a potential to increase the amount of possible colors beyond a full range of reflective or diffuse surface colors. With virtual reality glasses, the poten- tial stage for storytelling is also now like a theater in the round — where typically props and sets are minimal, and char- acters and story are exposed using less visual treatment. Shakespeare would have been ready with advice for the actors to do their part. SPEAK THE SPEECH "Speak the speech," Shakespeare wrote, perhaps meaning that the result would then be more real. As for the rest of the performance and its presentation qual- ities, perhaps the best overall advice to content creators working behind the audi - ence, when everything is wide open, is to pay careful attention to how the dimen- sional opportunities to perform can be limited to be effective to your story telling. Let opportunity help you to redefine what your comfortable level on screen reality, performance and believability is. In other words, sometimes more can mean less.The ability to reproduce high dynamic range from a camera system through to the display, for instance, can add depth to your images. The accentua- tion of contrast can also deliberately limit, This shot, from an HDR camera, shows how dynamic range helps authenticate CGI. 4K HDR AND Photos courtesy of VTP

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