RE: NEC PA271Q "Native" chromaticities
RE: NEC PA271Q "Native" chromaticities
- Subject: RE: NEC PA271Q "Native" chromaticities
- From: Wayne Bretl via colorsync-users <email@hidden>
- Date: Sat, 30 Nov 2019 19:23:00 -0700
Regarding NTSC phosphors:
The original NTSC phosphors, developed by RCA and used in the 15GP22 CRT (15
inch OD, 12 inch picture), used the old P1 (oscilloscope / radar screen)
green, and a non-sulfide blue. The non-sulfide blue was not as deep into the
violet blue as desired, but the sulfide gave problems in manufacturing due
to copper contamination turning it green. These phosphors were carried into
the first 21 inch CRTs, but sometime soon after, the sulfide blue was
introduced, moving the chromaticity to the vicinity of today's sRGB blue.
The red went through various changes giving increased efficacy, but the
unequal gun current ratios were still a problem, so RCA and others settled
on the 9300K+27MPCD white point, which essentially meant a very cyan white.
In the early 1960s, all-sulfide tubes were introduced, which used a high
proportion of cadmium to obtain the red phosphor. Where the other reds that
had been used were close to NTSC, the sulfide red was a bit more orange at
low currents and considerably more orange in the highlights. The sulfide
green was much yellower than P1, as seen in the sRGB spec. Some TV CRT
makers included a bit of cadmium in the green sulfide phosphor as well,
making it even yellower and cutting the cyan edge of the gamut even worse
than sRGB. In the mid to late 60s rare-earth reds were introduced, making
the gun currents closer to unity ratio, and returning the red chromaticity
close to NTSC. This is the red you see in the sRGB spec. The cadmium was
also dropped from the sulfide green due to environmental concerns (a
combination of needing to eliminate cadmium from factory waste, and the high
cost of doing so.) So, the SMPTE monitor specs, and European PAL system
specs, ended up being essentially sRGB with minor differences, which were
eventually settled as the sRGB/HDTV specs.
Wayne
-----Original Message-----
From: colorsync-users
<colorsync-users-bounces+waynebretl=email@hidden> On Behalf Of
Roger Breton via colorsync-users
Sent: Saturday, November 30, 2019 9:37 AM
To: 'Wire ~' <email@hidden>
Cc: ''colorsync-users?lists.apple.com' List'
<email@hidden>
Subject: RE: NEC PA271Q "Native" chromaticities
Wire,
Is this what you're looking for?
https://1drv.ms/u/s!AkD78CVR1NBqkoAteG-cIdVA_xRmmA?e=EgcKHL
Opinion about balance between AdobeRGB and Display P3 in consumer gear?
Honestly, I don't know. I don't know at what rate are wide-gamut monitor
prices coming down? I'm not sure many "consumers" care all that much or are
the least bit knowledgeable about the gamut of their displays? As far as
Apple's products are concerned, it may give their engineers "good
conscience" to know they are adopting a "new" standard for display, P3, but
I suspect most buyers are not all that preoccupied and certainly wouldn't be
swayed to buy an Apple product because of their "adoption" of P3. I read
elsewhere that Microsoft's Surface Hub has P3 as its "native" space?
As an experiment, I tried to set my PA271W in its native gamut, if only to
measure the primaries, but I quickly reverted to sRGB emulation because the
colors were too vivid?
You mentioned NTSC and I was surprised to see how far it reaches into the
greens, not so much into the blues but almost on the nose of the spectrum
locus for the red primary. Quite a feat. Could it be that televisions were
made with these primaries all the way back in the '60s, '70s, '80s, '90s?
/ Roger
-----Original Message-----
From: colorsync-users
<colorsync-users-bounces+graxx=email@hidden> On Behalf Of
Wire ~ via colorsync-users
Sent: Saturday, November 30, 2019 9:49 AM
To: email@hidden
Subject: Re: NEC PA271Q "Native" chromaticities
Roger thanks (and Andrew) for looking that up and plotting.
Would you replace previous NEC model plot with NTSC 1953 and post your graph
over on the DisplayCal thread you recently commented... The graph clearly
makes Vincent at DisplayCal's point about combined P3 / Adobe coverage
possible with some new tech. And I think it will show that consumer displays
(higher end) have finally arrived at the color spec laid down when ENIAC was
the next big thing (figuratively haha)
What are you opinions about the balance between Adobe RGB and Display P3
coverage in consumer gear? And challenges of wide-gamuts in general. I'm
interested in your opinions as both what you think personally and your sense
of industry trends.
/wire
On Fri, Nov 29, 2019 at 6:40 PM Roger Breton via colorsync-users <
email@hidden> wrote:
> Thank you so much, Mr Rodney.
> Never knew why manufacturers could not publish this kind of data in
> their technical brochure.
>
> A little graphing shows the improvements over the previous generation:
> https://1drv.ms/u/s!AkD78CVR1NBqkoAglHEpfO10xKmr_g?e=npCj5r
>
> I can see they managed to get the red primary very close to the
> Cine-P3 red primary which, according to the P3 specs, is "made up of a
> 615nm monochromatic" source of light.
>
> The green primary gives the impression that it is cleverly "sitting"
> between
> AdobeRGB's green primariy and Cine-P3's green primary.
>
> The blue primary is also improved relative to the 271W.
>
> I can't assess the black level, though. Being an OLED panel, it's
> supposed to have deeper black levels than an LCD panel.
>
> I suppose you have a 10-bit end to end workflow?
>
> May I ask the source of your numbers, Andrew? I1pro2? Multiprofiler?
> SpoectraView II? I found Multiprofiler numbers are very close to
> lab-grade instruments, at least in my experience.
>
> Thank you so much for your help,
>
> / Roger
> www.graxx.ca
>
> -----Original Message-----
> From: Andrew Rodney <email@hidden>
> Sent: Friday, November 29, 2019 9:13 PM
> To: Roger Breton <email@hidden>
> Cc: 'colorsync-users?lists.apple.com' List <
> email@hidden>
> Subject: Re: NEC PA271Q "Native" chromaticities
>
> Here's what I see on mine, (full gamut) in SpectraView Info window:
>
> Red: 0.683, 0.311
> Green: 0.217, 0.721
> Blue: 0.153, 0.045
> Source: Calibration Sensor.
>
> Hope that's useful.
>
> Andrew Rodney
> http://www.digitaldog.net/
>
>
>
> > On Nov 29, 2019, at 7:04 PM, Roger Breton via colorsync-users
> <email@hidden> wrote:
> >
> > Would anyone have the 1931 CIE xy chromaticities of this monitor, by
> > any chance? In its "Full", "Native" mode? It's not in the User
> > Manual, it's not on NEC web site, it's not on some user review by
> > PCMag or some other? It's probably shown on Multiprofiler but I
> > don't have the version made for this monitor.
> >
> >
> >
> > Curious to know how they can go about emulating both AdobeRGB and
> > DCI-P3 at the same time.
> >
> >
> >
> > Any help is appreciated / Roger
>
>
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