Panasonic G20 Calibration: Colour - AVS Forum
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post #1 of 11 Old 11-04-2011, 04:16 AM - Thread Starter
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Hi Everyone

I am a bit of a newb when it comes to calibrating, and I apologise if this is a dumb question.

I have a Panasonic G20B UK plasma, and was going through the notions of calibrating it using an iDisplay 3 retail, Calman 4.4 and the latest AVSHD DVD (2.0d). I got the grayscale to be spot on, but I ran into a few difficulties getting the colour to spec. Before I try again getting the colour right, I spent some time trying to read up a bit more on calibration, and what other users have done with the G20.

Specifically, I am a bit confused on what I have read on the CMS of the G20: In the colour management menu, one has the options to change the Hue (R,B,G) and Saturation (R,B,G) settings. Now, I had thought that the Saturation settings only affected the primary colours, and the Hue settings only adjusted the secondary colours, and hence on my first calibration attempt, I was trying to get the primaries right by only adjusting the saturation settings, and then moving to the secondaries by adjusting the hue settings. I couldnt get the colours to lie in their respective places on the triangle, and also couldnt get the DeltaL and DeltaH readings to be below 3.

However, on a review of the G20 on another website, the author stated that "This is a 2D CMS system and only affects primary colours..."

So have I been using an incorrect approach when calibrating colour on the G20, in the sense that the Saturation and Hue settings actually only apply to the primary colours, and there is nothing I can do on where the secondaries end up on?

Would anyone have any tips for me that are specific to calibrating the G20 display?

Thank you all for your kind help
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post #2 of 11 Old 11-04-2011, 11:19 AM
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Hue can effect primary colors as well.

When a color is full saturated it has only that primary as a component.
But when you desaturate it you add both of the other primaries, so the hue setting effects the ratio of the other two primaries.

You can't shift them much, but especially on something like a wildly oversaturated green you should be able to do a better job of bringing it back to the correct green.


The secondaries should follow the primaries, with a neutral color decoder the secondaries should lie on a line between the two primaries at a point where a line through the white point and the third primary intersect.

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post #3 of 11 Old 11-05-2011, 10:35 AM
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Man, you got a lot of wrong information about the adjustments...

The 3 dimensions of color are hue, saturation, and brightness (or Luminance). In this case hue is completely unrelated to the hue/tint control in most basic settings menus.

In this case "hue" means that the shade of red is accurate so that it is not offset towards orange or magenta. "Saturation" means the intensity of the color, and brightness/luminance is how... well, bright (or dark) the color is. The CMS controls in your TV are 2D because there is no brightness/luminance control, not because of any other reason.

That said, the Panasonic CMS controls don't work very well... there's a lot of "bleed" into parameters the control should not be affecting, as you have found out. The only way to deal with that is to make adjustments over and over again until everything is as accurate as it can be made. Because there are no brightness/luminance CMS controls, you will not be able to do much to improve brightness/luminance.

You may find that changing CalMAN to uvL color makes it easier to set the Panasonic CMS controls. uvL color space measures hue with the "u" coordinate, saturation with the v coordinate and luminance with the L coordinate. You are probably in xyY space right now... it is much trickier to use the Panasonic CMS controls while you are measuring in xyY space because the hue and saturation controls will change both x and y when you adjust them. In uvL space, the CMS controls will be more focused on a single coordinate (but there is still some 'overlap'). To change to uvL space, you have to change the preferences (right click) for each graph to uvL.

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post #4 of 11 Old 11-05-2011, 12:57 PM
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Quote:
Originally Posted by Doug Blackburn View Post

Man, you got a lot of wrong information about the adjustments...

The 3 dimensions of color are hue, saturation, and brightness (or Luminance). In this case hue is completely unrelated to the hue/tint control in most basic settings menus.

In this case "hue" means that the shade of red is accurate so that it is not offset towards orange or magenta. "Saturation" means the intensity of the color, and brightness/luminance is how... well, bright (or dark) the color is. The CMS controls in your TV are 2D because there is no brightness/luminance control, not because of any other reason.

That said, the Panasonic CMS controls don't work very well... there's a lot of "bleed" into parameters the control should not be affecting, as you have found out. The only way to deal with that is to make adjustments over and over again until everything is as accurate as it can be made. Because there are no brightness/luminance CMS controls, you will not be able to do much to improve brightness/luminance.

You may find that changing CalMAN to uvL color makes it easier to set the Panasonic CMS controls. uvL color space measures hue with the "u" coordinate, saturation with the v coordinate and luminance with the L coordinate. You are probably in xyY space right now... it is much trickier to use the Panasonic CMS controls while you are measuring in xyY space because the hue and saturation controls will change both x and y when you adjust them. In uvL space, the CMS controls will be more focused on a single coordinate (but there is still some 'overlap'). To change to uvL space, you have to change the preferences (right click) for each graph to uvL.

Hi Doug,

I'm not sure uvL is as you describe are you refering to the 1976 u'v' color space that is the alternate gamut view?

That is more perceptual uniform that 1931 xy color space, but it is conceptually the same.

There is also CIE L*U*V* which is a 3D color space very similiar to CIEL*a*b*

It is true that you can calculate a Chroma and Hue component for either L*U*V* or L*a*b* and those would be the values you'd want to calibrate to, but I'm not sure they are available in CalMAN 4.

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post #5 of 11 Old 11-06-2011, 10:33 AM
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CalMAN has uv color space options for dE calculations as well as for the CIE chart... the CIE chart for uv and xy look similar but are rotated somewhat and the "green" area of the uv CIE chart is quite a bit smaller than the blue and red space while in the xy CIE chart, green, red, and blue occupy about the same "area" (more or less).

uvL space is best conceptualized as a cylindrical color space with the color (u) around the circumference of the cylinder, saturation (v) along the radius of the cylinder, and L (luminance) along the center axis (white on one end, black on the other end). Of course the space is really cylindrical, its a little more football shaped on the ends as you approach white and black. But the cylinder concept works well enough to get the idea of how this space works. CalMANs implementation of uvL space more closely tracks what hue, saturation, and luminance CMS controls do when trying to move colors around than sticking with xyY which. When you select the uv space for the CIE diagram, the hue and saturation controls in most CMSs are easier to work with as the measurements more closely track the moves you make with the CMS controls.

When the CMS controls are hue, saturation, and luminance, it is easier to "steer" each color into the reference "box" for each color in the CIEuv chart as the CMS controls correspond to horizontal and vertical placement on the CIE chart. If you are looking at an xy CIE chart, the CMS controls will likely move the measurement some flavor of diagonal making it harder to "steer" your measurement into the small "reference" box CalMAN places on the reference points on the CIE chart.

One thing I noticed about CalMAN though... if you select dEuv for color measurements, you really only get u and v in the dE calculation -- it would be nice if you got u,v, and L (a 3D dE number) so you'd have a clear indication of the OVERALL accuracy of each primary and complimentary color. But CalMAN does show the CIE chart in uv space as well as an L graph so you can see the dE number for the CIE chart and how close the luminance is on the luminance graph, you just don't get all 3 parameters in the dE calculation.

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post #6 of 11 Old 11-06-2011, 10:54 AM
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Quote:
Originally Posted by Doug Blackburn View Post

CalMAN has uv color space options for dE calculations as well as for the CIE chart... the CIE chart for uv and xy look similar but are rotated somewhat and the "green" area of the uv CIE chart is quite a bit smaller than the blue and red space while in the xy CIE chart, green, red, and blue occupy about the same "area" (more or less).

uvL space is best conceptualized as a cylindrical color space with the color (u) around the circumference of the cylinder, saturation (v) along the radius of the cylinder, and L (luminance) along the center axis (white on one end, black on the other end). Of course the space is really cylindrical, its a little more football shaped on the ends as you approach white and black. But the cylinder concept works well enough to get the idea of how this space works. CalMANs implementation of uvL space more closely tracks what hue, saturation, and luminance CMS controls do when trying to move colors around than sticking with xyY which. When you select the uv space for the CIE diagram, the hue and saturation controls in most CMSs are easier to work with as the measurements more closely track the moves you make with the CMS controls.

When the CMS controls are hue, saturation, and luminance, it is easier to "steer" each color into the reference "box" for each color in the CIEuv chart as the CMS controls correspond to horizontal and vertical placement on the CIE chart. If you are looking at an xy CIE chart, the CMS controls will likely move the measurement some flavor of diagonal making it harder to "steer" your measurement into the small "reference" box CalMAN places on the reference points on the CIE chart.

One thing I noticed about CalMAN though... if you select dEuv for color measurements, you really only get u and v in the dE calculation -- it would be nice if you got u,v, and L (a 3D dE number) so you'd have a clear indication of the OVERALL accuracy of each primary and complimentary color. But CalMAN does show the CIE chart in uv space as well as an L graph so you can see the dE number for the CIE chart and how close the luminance is on the luminance graph, you just don't get all 3 parameters in the dE calculation.

ChromaPure allows you to choose CIELUV as a dE formula. The CIE diagram is xy only, though.
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post #7 of 11 Old 11-06-2011, 11:53 AM
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Quote:
Originally Posted by Doug Blackburn View Post

uvL space is best conceptualized as a cylindrical color space with the color (u) around the circumference of the cylinder, saturation (v) along the radius of the cylinder, and L (luminance) along the center axis (white on one end, black on the other end). Of course the space is really cylindrical, its a little more football shaped on the ends as you approach white and black. But the cylinder concept works well enough to get the idea of how this space works. CalMANs implementation of uvL space more closely tracks what hue, saturation, and luminance CMS controls do when trying to move colors around than sticking with xyY which. When you select the uv space for the CIE diagram, the hue and saturation controls in most CMSs are easier to work with as the measurements more closely track the moves you make with the CMS controls.

Doug there is no such thing as uvL at least in CalMAN. We have the u'v' color space which is the 2d color space used for CIE Diagram.

There is also CIE L*U*V* but the U*V* are still plotted in a standard 2d cartesian plane. It is calculate based on your white point so 0,0 is white. This makes it possible to calculate the Hue as an angle and saturation as a distance from 0,0. CIE L*a*b* works the same way, and that is what is being calculated to create the DE94 L,C,H components.


There are color models that work as you describe, but they are HSL and HSV, neither of which are in CalMAN.

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post #8 of 11 Old 11-06-2011, 12:03 PM
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Originally Posted by PlasmaPZ80U View Post

ChromaPure allows you to choose CIELUV as a dE formula. The CIE diagram is xy only, though.

That's the problem with a software that is limited in it's capability. It works exactly the way it's author wants it to work.

It's a lot harder to make something with the flexibility to see the data any way you want to see the data.

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post #9 of 11 Old 11-07-2011, 09:48 AM
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Originally Posted by sotti View Post

Doug there is no such thing as uvL at least in CalMAN. We have the u'v' color space which is the 2d color space used for CIE Diagram.

There is also CIE L*U*V* but the U*V* are still plotted in a standard 2d cartesian plane. It is calculate based on your white point so 0,0 is white. This makes it possible to calculate the Hue as an angle and saturation as a distance from 0,0. CIE L*a*b* works the same way, and that is what is being calculated to create the DE94 L,C,H components.


There are color models that work as you describe, but they are HSL and HSV, neither of which are in CalMAN.

Maybe the labels in CalMAN need to be updated for the next release then, they currently say "uv" everywhere (gamut and grayscale) where they should probably say u'v'. Even though it's u'v' it still seems more intuitive to use when adjusting Hue and Saturation CMS controls (compared to xy).

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post #10 of 11 Old 11-07-2011, 01:43 PM
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That's the problem with a software that is limited in it's capability. It works exactly the way it's author wants it to work.

It's a lot harder to make something with the flexibility to see the data any way you want to see the data.

Well, there are two sides to this. The benefit of everything being preset/pre-configured is that you can do a full calibration without having to change any settings or options (aside from the very basic options you can set). This makes the software extremely easy to use and you don't end spending time customizing everything to your liking/preferences. There is virtually no learning curve to getting the most out of this software, thanks to it's simple layout and abundant help menus.

The downside is that if and when you want to customize layouts and charts/graphs, you simply cannot. CalMAN does require a bit more technical skill to get the most out of it, but like you mention, you can customize virtually everything in the workflows (and even make your own if you're feeling ambitious). There is a steeper learning curve here, but the end result can be rewarding when you create/modify a workflow to make it show exactly what you want it to show in the way you want to show it.
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post #11 of 11 Old 11-07-2011, 03:44 PM
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Originally Posted by PlasmaPZ80U View Post

Well, there are two sides to this. The benefit of everything being preset/pre-configured is that you can do a full calibration without having to change any settings or options (aside from the very basic options you can set). This makes the software extremely easy to use and you don't end spending time customizing everything to your liking/preferences. There is virtually no learning curve to getting the most out of this software, thanks to it's simple layout and abundant help menus.

The downside is that if and when you want to customize layouts and charts/graphs, you simply cannot. CalMAN does require a bit more technical skill to get the most out of it, but like you mention, you can customize virtually everything in the workflows (and even make your own if you're feeling ambitious). There is a steeper learning curve here, but the end result can be rewarding when you create/modify a workflow to make it show exactly what you want it to show in the way you want to show it.

That is absolutely true.

Although I do believe the current interface can be simplified to the point where you could just load something and have it be that easy if you wanted it.

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