3 ms·

To the first point, yes, I'm just being pedantic. But for the second point, how is that relevant? I'm not sure how this helps, because a) this has nothing to d

To the first point, yes, I'm just being pedantic. But for the second point, how is that relevant? I'm not sure how this helps, because a) this has nothing to do with the display, i.e. we could modify an image to show the same effect on all displays, and b) gamut has not become wider at all.

jacobolus 7y ago
It has to do with the display because recent displays can get much brighter than displays of the past. Instead of reaching a luminance of 80 of 100 nits, they can now reach 1000 or even 5000 nits. What this means is that it is now possible to set the target “diffuse white” luminance to be something like 200 nits, but then still be able to produce colors in which any (or all) of the primaries is 5x more intense than that. Until recently, it has been assumed that display white is (100%, 100%, 100%), whether the maximum display brightness happens to be 50 or 500 nits. But when displays can get to 1000 nits or beyond, that is no longer a tenable assumption. * * * If you have a conventional display (say a non-HDR TV or smartphone) you could still crank the display brightness all the way up but only show images or video where diffuse white was set to 20% of maximum (or whatever), and thereby achieve an expanded gamut for bright colors. But in practice few people if any ever did that. You can even do the same thing with a painting: if you make your painting overall darker than usual, place it on a dark gray wall, and then shine a very intense light on it, you can give your painting more dynamic range and a larger color gamut than you would otherwise be able to achieve with the same materials. This technique has been used to good effect by some (but relatively few) master painters, photographers, etc.
- rubatuga 7y ago
  I'll try to summarize: if we are not physically getting a new combination of RGB cone stimulation ratios in our retinas, then the colour gamut has not become "wider". When compared to a SDR display, your HDR display that you mention above cannot display a RGB cone stimulation ratio that is not already achievable on the SDR display.

jacobolus 7y ago

It has to do with the display because recent displays can get much brighter than displays of the past. Instead of reaching a luminance of 80 of 100 nits, they can now reach 1000 or even 5000 nits. What this means is that it is now possible to set the target “diffuse white” luminance to be something like 200 nits, but then still be able to produce colors in which any (or all) of the primaries is 5x more intense than that. Until recently, it has been assumed that display white is (100%, 100%, 100%), whether the maximum display brightness happens to be 50 or 500 nits. But when displays can get to 1000 nits or beyond, that is no longer a tenable assumption. * * * If you have a conventional display (say a non-HDR TV or smartphone) you could still crank the display brightness all the way up but only show images or video where diffuse white was set to 20% of maximum (or whatever), and thereby achieve an expanded gamut for bright colors. But in practice few people if any ever did that. You can even do the same thing with a painting: if you make your painting overall darker than usual, place it on a dark gray wall, and then shine a very intense light on it, you can give your painting more dynamic range and a larger color gamut than you would otherwise be able to achieve with the same materials. This technique has been used to good effect by some (but relatively few) master painters, photographers, etc.

rubatuga 7y ago
I'll try to summarize: if we are not physically getting a new combination of RGB cone stimulation ratios in our retinas, then the colour gamut has not become "wider". When compared to a SDR display, your HDR display that you mention above cannot display a RGB cone stimulation ratio that is not already achievable on the SDR display.