[Tig] Wide Gamut displays

[Dave Corbitt]

On May 26, 2007, at 4:15 PM, Bob Friesenhahn wrote:
> On Sat, 26 May 2007, David Tosh wrote:
>>
>> I've seen a lot of LCD monitors touting "105%" or "110%" of NTSC color
>> space. Not that any consumers will know but, hey it's more so it must 
>> be
>> better. And as LED back light becomes affordable, the specsmanship 
>> will
>> become irresistible.
>
> I think that this is another way of saying that the RGB primaries are
> way off. :-)
>
> There can never be more than 100% of NTSC color space so these
> displays must be carving out a piece of uncharted territory.
>
>
> Bob Friesenhahn
>

Gentlemen,

When marketers refer to a percentage of NTSC colorspace, they are 
referring to the 1953 NTSC color primaries that were indeed the largest 
or widest gamut colorspace ever implemented until fairly recently. Due 
to the primitive hardware available back then, the original wide gamut 
colorspace of the 1953 NTSC proved impractical and was brought in to a 
smaller colorspace for practical engineering reasons, and that's why we 
wound up with the much smaller colorspace of SMPTE-C and EBU which 
eventually morphed in to Rec 709. BUT, 1953 colorspace is indeed a true 
wide gamut colorspace with some vivid jewel tone colors (emerald 
greens, turquoises, and ruby reds) that are not reproducible with our 
current display standards. It is possible to have a larger colorspace 
than 1953 NTSC. Just look at the CIE chart with old NTSC primaries 
plotted on it and you will see that there are still colors visible to 
the human eye that are outside the NTSC triangle. So if a wide gamut 
display system chooses primaries that map beyond the CIE coordinates 
for 1953 NTSC, then indeed you can come up with numbers like 110% of 
NTSC.

Another thing you can do with a wide gamut display is you can use 
correction matrices to emulate any color space smaller than your RGB 
triangle. So, theoretically, a wide gamut display, if designed 
properly, could have settings for 1953 NTSC, SMPTE-C, EBU, Rec 709, 
sRGB, Adobe RGB, or any other choice you make as long as the raw 
display primaries create a larger triangle on the CIE chart than any of 
your chosen display colorspaces. And that is where accuracy comes in to 
the story. My question is, is anyone doing this other than high end DI 
facilities writing their own LUTs for their big DI theater projectors?

Once again, a wide gamut display does no one any good unless the entire 
chain of deliverables from start to finish is designed to sense these 
wider gamuts and pass them on all the way to the display device 
accurately and faithfully, which means carefully specified standards.

Disclaimer: You know who I am. Always ready to stir it up but I am a 
manufacturers rep.

Enjoy the holiday weekend (for those in the US). Everyone else should 
enjoy their weekend too :-)

Dave Corbitt
FrontNICHE North America
Eastern Sales Manager
Summit, NJ 07901
http://www.frontnichena.com/