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bbcolor
Joined: 10 Aug 2018 Posts: 1
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Link Posted: Sat Aug 11, 2018 4:04 pm Post subject: Need Help: CMS HSB HCFR |
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(I'm new to this forum and to forums-in-general, so apologies if I've broken forum ediquette I'm not aware of).
The short:
I'm needing assistance on how Hue Saturation and Brightness affect xyY of an individual color. (I assume those are the values I am checking to evaluate correct color).
Does an increase/decrease in hue increase/decrease x or y or Y?
Does an increase/decrease in saturation increase/decrease x or y or Y?
Does an increase/decrease in brightness increase/decrease x or y or Y?
I understand my test data compared to reference standards (why it needs to be corrected), but when attempting to correct color using HSB in the color tuner, I'm not understanding which variable to manipulate in what way and in what order to achieve correction for each color.
The long:
I'm calibrating my Vizio M401i-A3 TV using the guide on this forum. http://www.curtpalme.com/forum/viewtopic.php?t=10457, HCFR software, and a Spyder5 colorimeter.
I've completed the contrast, brightness, and greyscale adjustments using offset and gain as well as 11 point greyscale with good results and low deltaE.
I'm using my TV's built in color bar pattern to test primaries and secondaries with color and tone +-0 and all HSB settings at 0. I've completed an initial test of my colors using HCRF. My red has deltaE 9.3, green deltaE 3.2. blue deltaE 1.2.
The problem:
I've attempted both subtle and extreme HSB adjustments for red, attempting to correct the color. Even the extreme adjustments don't seem to result in significant changes in xy, while Y is affected easily using saturation and brightness. I'm unable to achieve correction. I'm also having difficulty adjusting green and blue and HSB seem to affect each primary's xyY differently. While blue has a low deltaE, the Y value is off, and even extreme Y adjustment does not bring the Y value to correct percentage of white Y.
So I feel stuck not knowing how to achieve color correction because I can't discern which HSB value to adjust, in what order, and to what degree. I'm not seeing the linearity of input (changing the HSB) to output (change in xyY).
Side note: I'm using the color bar pattern because using the 100% pattern and then filtering color using the color tuner results in HSB having no discernible affect. This could be related to my above problem, but it could also be the proper way to measure, I'm just having a placebo in my experimentation.
Any assistance or pointing me in the right direction is appreciated!!!
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wanderer
Joined: 11 Jan 2015 Posts: 63
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Link Posted: Sat Aug 18, 2018 3:01 am Post subject: |
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Does your television have a CMS at all? That's about your only hope in moving around the primary (RGB) or secondary (CMY) colors to align up to their correct corner\edge locations. Typically that option was added on some models so that you could move these corner targets around. Often the CMS would fix one thing being your corner target, then mess up a whole bunch of other stuff running from black to white, introducing banding, etc.
If we presume that your meter, software and patterns are reading correctly then red is oversaturated and doesn't cover the REC.709 color space in that corner. Even a 3D LUT device won't fix this red corner issue. What you are seeing here may just be the best your display can do given it's design. This is actually really common in that most modern displays won't be able to give you a proper REC.709 color space, especially the cheaper models which is the bulk of the market. If you take readings at the 25, 50, 75% saturation levels in addition to the corner you'll likely find they are all over the map as well.
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kal Forum Administrator
Joined: 06 Mar 2006 Posts: 17850 Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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Link Posted: Sat Aug 18, 2018 2:21 pm Post subject: |
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wanderer wrote: | Does your television have a CMS at all? That's about your only hope in moving around the primary (RGB) or secondary (CMY) colors to align up to their correct corner\edge locations. |
Bingo! That is correct.
wanderer wrote: | Often the CMS would fix one thing being your corner target, then mess up a whole bunch of other stuff running from black to white, introducing banding, etc. |
This is unfortunately often the case with many displays. Because if this how these controls work is not always the same between display models.
Good luck!
Kal
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