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Discussion Starter · #1 ·
Hi,


I need some help regarding setting up the Colour brightness on a Sony Plasma.


1) The Sony has a Blue only mode' in the service menu. Switch this on and the image goes Black and white. I then display a 75% SMPTE colour bar on screen. Using a light meter, I adjust the colour brightness of the Blue bar to match that of the white bar.

2) I have also set the colour brightness using HCFR' with an Eyeone' probe.


Guess what? I get different results from both methods? Example, colour control setting for HCFR' is -30, colour setting for Blue only mode' is -20. Both methods seem very scientific. However, which one is more accurate? When the HCFR is set correctly there are no major errors showing on the blue channel to suggest that there should be this type of discrepancy.


Thanks
 

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Quote:
Originally Posted by delphiplasma /forum/post/18313686


I get different results from both methods? Example, colour control setting for HCFR' is -30, colour setting for Blue only mode' is -20. Both methods seem very scientific. However, which one is more accurate?

I did a similar comparison with a "blue filter" and colorimeter on my plasma TV. The settings were very different. The "blue filter" method over exaggerated the colors and the i1 Display LT metered color setting was much lower and more accurate - natural to my eyes.


Check out these related threads for more test data and detailed info:

http://www.avsforum.com/avs-vb/showthread.php?t=1192824

http://www.avsforum.com/avs-vb/showthread.php?t=1230641
 

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Simply put, the blue only or blue filter approach assumes the display has a standard gamut (Rec. 709 or SMPTE-C) and accurate color decoding (Rec. 709 or Rec. 601). However, most displays don't have perfect gamuts or perfect color decoding. Therefore, setting color correctly for the brightness of blue and tint correctly for the hue of cyan doesn't guarantee the brightness of green and red or the hues of yellow and magenta will be correct.


Since skintones are based mostly on red and yellow, getting those two right with color/tint controls is usually the best you can do without a CMS. Getting blue & cyan right will not achieve this unless your gamut and color decoding are perfect or extremely close to perfect.


What's more is that even getting blue/cyan right with the blue only method is an approximation at best since my meter revealed the blue only mode set color too low for the brightness of blue and the hue of cyan was close to where it should be but it was still a little off and could have been improved with my meter if I chose to focus on cyan.
 

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Quote:
Originally Posted by delphiplasma /forum/post/18313686


Hi,


I need some help regarding setting up the Colour brightness on a Sony Plasma.


1) The Sony has a ‘Blue only mode’ in the service menu. Switch this on and the image goes Black and white. I then display a 75% SMPTE colour bar on screen. Using a light meter, I adjust the colour brightness of the Blue bar to match that of the white bar.

2) I have also set the colour brightness using ‘HCFR’ with an ‘Eyeone’ probe.


Guess what? I get different results from both methods? Example, colour control setting for ‘HCFR’ is -30, colour setting for ‘Blue only mode’ is -20. Both methods seem very scientific. However, which one is more accurate? When the HCFR is set correctly there are no major errors showing on the blue channel to suggest that there should be this type of discrepancy.


Thanks

Just to be sure, the color space chosen in HCFR is SD and not HD? Otherwise, you might be comparing SD color bars to an HD reference in HCFR. Also, you're using 75% color patterns for your meter to match the 75% color bars?
 

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Discussion Starter · #5 ·
Thanks for the replies. I did use 75% SMPTE bars as specified by Sony. What I have done is SETTLE FOR A MID POINT BETWEEN THE 2 METHODS.21% RED. Slightly higher blue, and slightly worse delta E.
 

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Discussion Starter · #6 ·
Ok. I had 3 choices of colour brightness to choose from:


-30 = best delta E values all under 10

-25 = adjust red for 21%

-20 = best blue only mode adjustment.


Out of the above 3 the colour quality at -30 is the best (Red 17%). At -25 the colour is just a little over the top. -20 Forget it! (Red 23%)
 

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Quote:
Originally Posted by delphiplasma /forum/post/18330248


Ok. I had 3 choices of colour brightness to choose from:


-30 = best delta E values all under 10

-25 = adjust red for 21%

-20 = best blue only mode adjustment.


Out of the above 3 the colour quality at -30 is the best (Red 17%). At -25 the colour is just a little over the top. -20 Forget it! (Red 23%)

A few questions:

Is -30 'negative' 30? If so, that means lowest value of color is the best, right?

What are your measured x,y,Y values for red? Did you determine the Y percent for R=255 using the Lindbloom calculator? My results were very pleasing using Plasma54321's method .
 

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Discussion Starter · #8 ·
Sorry, my e-mail may not have been clear, -30 is the colour control setting on my plasma. So I have reduced the colour output by 30 steps. With regards the red brightness, I aimed for 21% of the 100% white. I'll mail my x,y Y values for red later.

I'll take a look at that link you sent.


Thanks
 

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Discussion Starter · #9 ·
OK, I've just re-done colour measurements with a Spyder 2 express (Previous measurements done with Eye One) and the measurement confers with the Blue only mode' settings, the CIE chart also looking more accurate.

However, the colour quality appears too bright to my eyes. Maybe the measurements are correct, as the colours, when I do the eyeball settings, are natural and never oversaturated, there are some program material where the colours appear to be de-saturated, but never oversaturated. Now I'm sure there is program material filmed with exaggerated colour saturation?
 

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Quote:
Originally Posted by delphiplasma /forum/post/18388194


OK, I've just re-done colour measurements with a Spyder 2 express (Previous measurements done with Eye One) and the measurement confers with the Blue only mode' settings, the CIE chart also looking more accurate.

However, the colour quality appears too bright to my eyes. Maybe the measurements are correct, as the colours, when I do the eyeball settings, are natural and never oversaturated, there are some program material where the colours appear to be de-saturated, but never oversaturated. Now I'm sure there is program material filmed with exaggerated colour saturation?

The spyder 2 is less accurate than the eye one, assuming the eye one hasn't drifted greatly.
 

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Discussion Starter · #11 ·
Thanks. I think it may have been the Settings on HCFR? Can someone remind me what the configration should be when taking measurements on a Plasma display?


1) HCFR - LCD setting, with filter on Spyder2


OR


2) HCFR - CRT setting, with filter off on Spyder2


Number 1 seemed to produce the nearest results to my Eye One and therefore has caused me to reduce the colour output down to a midway point between the 'Eye one' setting and 'Blue only mode' setting. So far the picture quality looks fine.
 

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Quote:
Originally Posted by delphiplasma /forum/post/18389653


Thanks. I think it may have been the Settings on HCFR? Can someone remind me what the configration should be when taking measurements on a Plasma display?

HCFR should be set to plasma under the Measures / Sensor (Configure) menu. Make sure you let the colorimeter warm up for at least 30 minutes on the TV before you start taking readings.
 

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Discussion Starter · #13 ·
Hi,


There is no plasma setting for the Spyder 2.


I think, baffle on and LCD mode seems to give nearest results to eye one.


Cheers!
 

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Quote:
Originally Posted by delphiplasma /forum/post/18402699


Hi,


There is no plasma setting for the Spyder 2.


I think, baffle on and LCD mode seems to give nearest results to eye one.


Cheers!

Oh. Sorry about that. I should have read a little closer.
 
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