I just listened to Scott Wilkinson response
to manufacturer's boast about their displays having a much wider gamut. Scott correctly points out that content (broadcast and Blu-ray) are mastered to a narrower gamut than what wide gamut displays are capable of, so he asks, what good is a wide gamut display? The manufacturer's response is that the content was originally filmed using a much wider gamut, which was shrunk only when transferred to Blu-ray or mastered for broadcast. The wide gamut display, the argument goes, merely restores these missing colors.
Let me explain why this is nonsense. In the first place this is nothing new. Manufacturers have been offering wide gamut displays for a long time. The original JVC LCoS projector, the RS1, had an extremely wide gamut. This is an old argument, but manufacturers keep recycling it as a way of convincing gullible consumers to purchase their products.
Second, while it is true that content is originally filmed using a wider gamut, most of the colors we see don't take advantage of the extra colors. Skin tones, trees, grass, sky are all composed of colors that fall well within the Rec. 709 HD standard. Only a relatively small percentage of the colors are lost when the gamut is shrunk to fit the HD standard.
Third, and most importantly, when remapping colors from a wide gamut source to a narrower gamut medium, the ONLY colors that are affected are those small number that are outside the HD gamut. The rest of the colors--the vast majority--stay the same. Think for a moment why this is true. If a skin tone naturally falls well within the HD gamut, you wouldn't want to change that color when remapping wide gamut source material to HD. That would visibly distort the skin tone. Only the relatively few very saturated colors will be remapped to fall within the HD boundary.
This explains why attempting to restore the original gamut by playing HD content on a wide gamut display is a bad idea. What the wide gamut display does is oversaturate ALL colors--including the skin tones I mentioned in the previous example. The display has no way of distinguishing between those colors that were compressed during the mastering process and those that weren't, so it indiscriminately increases the saturation of all of the colors.
BTW, there is one practical advantage to a wide gamut display for some users. If you have a good color management system, then it is useful to have as a starting point oversaturated colors that can then be desaturated to the correct HD standards. Other than this, manufacturer claims about wide gamut displays are unhelpful marketing hype that should be ignored.Edited by TomHuffman - 2/7/13 at 11:42am