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August 2015

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Page 36 of 51 35 POST AUGUST 2015 s the motion picture and tele- vision industries begin to work with higher resolutions, such as 4K (4,096x2,160 pixel image raster), and UHD (Ultra High Definition 3,840x2,160 pixel image raster), and examine de- livery methods for increased dynamic range, some questions arise as to what the additional resolution and the higher dynamic range can mean to the produc- tion processes. For television, such as sporting events, higher dynamic range can mean in- creased freedom of camera placement and framing, but the compositional dis- play choices are not necessarily convert- ible to standard range viewing. As well, for the television and movie industries, it can be argued that there is an impact as to some creative choice points of poten- tially accommodating, or not, greater col- or representation, since the perceptions of colors can change when the colors are represented in a lower light state, including states of desaturation, or when extended in high saturation. Further, due considerations should be given for adequate bit depth to preserve image fi- delity and prevent adverse display issues. Considerations can also be given for the added choice points in the adaptation of — or conversion of — high dynamic range compositions, similar to aspect ratio adaptations based on areas marked on camera viewfinders for "safe viewing," or similar to the use of viewfinder distinc- tions for exposure or contrast. Arguably, high dynamic range is perceived as having a greater impact on viewing than additional resolution, although it could be pointed out that the depth of modulation could in theory be needed to be twice as high for 4K/UHD viewing of normal contrast dynamic range in order to properly see that resolution even in square wave representation. When observing adjacent com- plementary hues, for example, it has been said that the viewer can perceive a strobe effect where they meet, but thin black lines (can) keep them under control (1). The additional resolution of the 4K image presentation allows for more subtle transitions in line, form, color, and tone. In visual effects layering, the treatment of the edges of forms, when they are set over complementary hues, may necessitate subtle blending to separate the forms from each other, and time variable manipulation, and relative transparencies of edge color correc- tion. Various production techniques to design or photographically-treat subjects and objects to be "read" against back- grounds, and the compositional aspects of framing and deep focus are poten- tially more important as to maintaining continuity and sensibility when viewing the combined images in higher resolution presentations. In theory, with more reso- THE STATE OF THE ART FOR 4K AND HIGH DYNAMIC RANGE AS MUCH A VISION FROM THE PAST AS IT IS FOR THE FUTURE BY CHRIS BONE, CTO, VTP, WWW.MYVTP.COM 4K HDR PART I A For television, higher dynamic range can mean increased freedom of camera placement and framing. AND SPECIAL REPORT:

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