Problems with calibrating new Samsung LED TV - AVS Forum
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Old 07-04-2013, 03:28 AM - Thread Starter
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Hi

I am trying to calibrate a new 42" F500 Samsung Full HD LED TV. With Chromapure and the HD Essentials disk, I can get very good tracking over the 20% to 100% stimulus range with dE between 0.7 and 1.5. However, at 15% and below, the output from the red and green seems to fall off significantly compared with the blue, so all the low level shadow detail has a bluish cast (At 10% the dE rises to about 15).

Is this something I am doing wrong or is it just a "feature" of this type of screen that there is much lower light output from the LED's or LCD at very low signal levels. All the Black detail, Skin tone etc special features are set to Off. Gamma is also between 2.2 and 2.3 except at the low end where it starts to rise to 2.6

PJG

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Old 07-04-2013, 09:09 AM
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Originally Posted by steppen View Post

Hi

I am trying to calibrate a new 42" F500 Samsung Full HD LED TV. With Chromapure and the HD Essentials disk, I can get very good tracking over the 20% to 100% stimulus range with dE between 0.7 and 1.5. However, at 15% and below, the output from the red and green seems to fall off significantly compared with the blue, so all the low level shadow detail has a bluish cast (At 10% the dE rises to about 15).

Is this something I am doing wrong or is it just a "feature" of this type of screen that there is much lower light output from the LED's or LCD at very low signal levels. All the Black detail, Skin tone etc special features are set to Off. Gamma is also between 2.2 and 2.3 except at the low end where it starts to rise to 2.6

PJG

most LCDs tend towards blue in the very dark end (some more than others, I believe the kind of panel you have matters (like S-PVA, A-MVA, or S-MVA)

unless you have more than 2-pt grayscale/white balance controls, you probably can't do too much to improve 5% to 15% (discard the 0% reading in terms of color... no meter can read xy correctly at luminance levels that low, just black level 'Y') without hurting higher levels like 20% to 50%
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Old 07-04-2013, 09:10 AM
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Old 07-04-2013, 09:48 AM - Thread Starter
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The meter is the X-Rite Display 3 which is an OEM version bundled with the Chromapure software. For my main cinema system, I also have the Lumagen 2012 video processor with full 3D cube calibration, so I am hoping to do a much better job on my JVC projector.

I was beginning to think that this was a physical problem with the display. Out of the box with Movie mode and Warm2 settings, the 42" Samsung was very accurate with dE in the 3-4 range except for the low end. I just had to tweek the RGB Gains and Offsets at 100% and 20% to get it to the current state. I think if I try to push the low end Red and Green, it will mess up the great mid range, so maybe I will just leave it as it is. I was just hoping that some other Samsung user had found a magic control to balance the sub 20% region

PJG

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Old 07-04-2013, 04:27 PM
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The higher end and larger screen-size Samsung TVs have 10-point grayscale calibration controls that allow you to dial in 10%, 20%, 30%, etc. individually The 10% adjustment step would likely fix the excess blue issue from 5% to 15%. If your model is limited to shadow and highlight grayscale controls, the problem you are having is a nonlinearity issue that COULD be engineered-out of the display, but they just aren't spending the money to do so at lower price points. All you can do is to partially fix the excess blue problem and live with the slight excess in yellow that you'll likely see from 20%-50% or so in order to make the blacks look less blue from 5%-15%. If the excess yellow is too distracting from 20% to 50%, then your only option is to live with the excess blue issue from 5%-15%. Getting the lowest error at each grayscale step is the calibration goal, but when there's a problem like the one you have, you get into the art of calibration where you try to balance errors so that overall errors are small(ish) when you can't completely eliminate a problem due to insufficienct controls. So if you have a 2 error at 20% and 15 error at 10%, you might have to accept an 8 error at 20% in order to get a 9 error at 10%. What you have going for you is that green errors are easiest to see while blue errors are the hardest to see. But since yellow is a mix of green and red, yellow errors are fairly visible also. So the art of compromise to get 20% and 10% looking decent at the same time is where you need to concentrate.

Another option would be to use one of the Lumagen processor's memories for calibrating the smaller TV... of course you'd have to run video for the small TV through the Lumagen processor which may not be practical, though there are some HDMI to Cat6 converters that would make the change possible by running Cat6 cable from the room with the TV to the room with the processor and back to the room with the TV (some of these systems require 2 Cat6 cables so you'd have to do 4 runs to make that solution work. Distance isn't much of an issue with the HDMI-to-Cat6 converters.

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Old 07-07-2013, 08:25 AM - Thread Starter
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Doug

Many thanks for your details reply. Unfortunately, my new 42" Samsung TV is not in the same house, let alone the same room as my Lumagen. I have already tried calibrating my in cinema 46" Samsung TV, but this is an older 2010 model and even with the Lumagen, it does not compare with the performance of the new unit. Amazing what 3 years can do. Both still have the same problem with fall off of red and green at low light levels, but the new 2013 version has so much better blacks, brightness and colour tracking. When I come to replacing my older Samsung, I will take your advice and look for a more upmarket model with the multi-step CMS, even if I don't need all the 3D and other smart internet stuff.

PJG

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