[QuadList] True colors

[James Snyder]

You have indeed hit on a major issue in the transition to non-CRT 
monitoring.  Unfortunately, the regulations that stopped the 
production of CRTs (the EU RoHS regulations forbade lead in glass, 
which is a key requirement for CRTs to not implode when evacuated) 
didn't give the industry enough time to create equivalent 
replacements in flat panels.  Also, in these days when signal quality 
is not as important, color purity and accuracy has not been a focus 
of many of the equipment manufacturers' biggest customers.

The issue is that professional CRTs were standardized decades ago 
around the SMPTE C phosphor and the definition of what 'black' and 
'white'.  Any monitor that complied with that standard reproduced 
SMPTE color bars in a definable, measurable, and reproducable way. 
No such standard currently exists for flat panels, although the SMPTE 
is working on defining a standardized monitor definition.

Until then, Sony has probably come the closest to the original SMPTE 
monitor definitions with their professional series LCD monitors and 
supposedly their new OLED monitors will allow you to change the 
monitor's color reproduction to match SMPTE C standard.  The only 
issue with the OLEDs is they only last about 3 1/2 years 
(continuously on; 30,000 hours total operational time if you turn 
them off) before they go yellow.  The LCDs come close, but you can 
never get them dead on in my experience.

Flanders Scientific also seems to get pretty close with their 
professional LCDs.

Plasma monitors are equivalent to CRTs (since they are, essentially, 
a CRT per pixel) and can get pretty close.  If any of them use SMPTE 
C phosphors, you're set.  I'm not aware of any that do, since SMPTE C 
phosphors tend to be much more expensive.

However, until an end-to-end standard is created, as it was with 
CRTs, accurate color reproduction with flat panels will not be 
possible.  When it does, it will most likely be based on how the 
monitors reproduce the colors from SMPTE color bars in a defined 
color standard (such as 601, 709, or XYZ color spaces).

James Syder
Library of Congress
Packard Campus for Audio Visual Conservation

>You have found one of the problems with panels.  The only way is to 
>pick one monitor brand and model only.  Sony has announced a panel 
>that will serve as a standard. 
>
>SMPTE had the 6500 degree standard as well as the EBU.  Basically at 
>this time, it is all up I the air.  There are groups working to set 
>a standard.
>
>Best of luck.
>
>Chris Hill
>
>On Dec 27, 2011, at 10:00 AM, Shai Drori <srdbx at netvision.net.il> wrote:
>
>>  Please excuse cross posting
>>  I have come across a problem that I wonder what is the best course 
>>of treatment. I have switched my video monitoring from Sony CRT to 
>>flat screens. The problem is that the colors look different in 
>>every monitor even in PAL video. Is there some sort of a color card 
>>or some method for me to correct the colors on the screens so that 
>>they "true" as much as possible? I can display several test 
>>patterns from my generator.
>>  Shai Drori
>  > Freelance