Synopsis:
For the last decade or more, creators of HD content have relied upon BVM-class CRT displays to make critical creative tone and colour judgements of their material. However, broadcast-grade CRT displays are no longer commercially available. It is questionable whether displays currently being advertised as “Grade 1” actually meet the needs of high-end content creators, and it is not yet clear exactly what specifications are required of emergent studio displays.
In this talk, I will discuss issues concerning faithful display of content in the post-CRT world. I will outline the behaviour of BVM-class CRT displays, and introduce the “GOGO” model, which incorporates gamma of about 2.4 (not 2.2, as commonly assumed, and documented in white papers by companies such as Sony and Panasonic). I will describe how LCD and plasma displays can be made to correspond to the BVM characteristics. I will discuss how gain and offset adjustments (commonly called CONTRAST and BRIGHTNESS) are introduced, why those names conflict with the common usage of the words (which refer to perceptual phenomena), and how the CONTRAST and BRIGHTNESS controls effectively perform the reverse of their names. I will introduce the very recent ITU-R agreement on elements of a standard EOCF for HD, augmenting BT.709. Finally, concerning image acquisition, the best-fit power function to the BT.709 camera “gamma” is not 1/2.2 or 0.45 as commonly assumed (and documented in white papers by companies such as Sony and Panasonic), but 0.51. I will describe why the 0.51 value is appropriate, and I will outline the origins of the confusion between that value and 0.45 (or “2.2”).
This talk is an abbreviated preview of the talk that I will present at HPA Tech. Retreat in February.