Greyscale charts in video and HD

Nine-step (“EIA”) charts have reflectance values arranged in an exponential relationship, r = 0.030 10^(0.18175 k), where k ranges 0 through 8. The reflectance steps correspond to uniform increments of optical density. These charts are typically called “logarithmic.” Eleven-step (“ITE‑J”) charts are designed to have reflectances that, when imaged by a video camera (having an OECF comparable …

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Gamma in studio and CE

HD content (a Blu‑ray movie for example) is properly and commonly mastered with displays (such as Sony BVM‑D32) having 2.4 gamma, at 100 nt reference white, with about 1 lx ambient illuminance, and a surround of about 1 nt (that is, 1% of reference white, a “very dim” surround). The 2.4 gamma is specified in BT.1886, and is well approximated by …

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