Monitor Color Gamut % compared to NTSC

we can see ads saying some monitor has 114% color gamut of NTSC gamut.
For exampe, Samsung says their XL series wide gamut monitors have
114% or 123%, according to their sites, compared to NTSC.

Does anyone know how exactly we calculate it? Is it in 3D space or 2D space?
If it is 3D space, it is pretty simple. As ColorThink Pro has color volume info.
But it seems not. Then how?

Thanks in advance.

If anyone has any ideas, I too would love to know how they various companies arrive at their figures.


I know that Eizo makes their comparisons using the equivalent of a 2D gamut projection. So this would be based on essentially a 2D outline of the gamuts. I’m pretty sure other manufacturers do the same.

As those familiar with ColorThink know, a 2D comparison of gamuts does not tell the whole story. There can be many portions of a seemingly small gamut that exceed those of a seemingly larger gamut (especially in shadow areas).

Also, when comparing gamuts, keep in mind the difference between coverage and size. A model might have 114% of the size of NTSC, but does it actually cover the same area (same colors) as the NTSC gamut? Any comparison between numbers like these should include size and coverage if you are really depending on this monitor to give you the gamut of something like AdobeRGB for example.

BTW, 3D gamut calculation like what’s done in ColorThink Pro is not so easy. We have always said that it is a coarse estimate. To be able to “wrap a skin” around a 3D gamut and calculate the volume of it is computationally expensive, and even more so the ‘finer’ you try to get. It works best on devices that have smooth transitions (like monitor profiles) and will be less precise on irregular printer profiles.