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post #1 of 27 Old 09-25-2018, 10:37 AM - Thread Starter
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TV Gamma HCFR

Hi everyone,

I've been using HCFR to calibrate my Panasonic TV and the results are good, however the gamma is way too off compared to the BT.1886 reference or any gamma reference like 2.2, 2.4, etc . In the image attached (gamma.jpg), you can see the results:

-the grey dotted line is the reference / target gamma BT.1886
-the yellow line is actually my TV gamma set to 2.6 (there are also other gamma options as 2.2 , 2.4, 2.5, however these are useless. 2.6 is the closest one)
-the cyan line is just the average gamma

I also attached the RGB gamma, the RGB Levels, and the gray scale measurements.

On my TV, I've been playing with "Contrast" and "Brightness" or switching between 2.2 to 2.6 and there's no way to get close to BT.1886 or 2.2, 2.4, etc. Even the the average gamma is always 1.8 or 2.0. There's also a BT.1886 gamma available, but it is useless. I can manually customize my TV gamma though using a maximum of 10 points and I get very close to the BT.1886, however sometimes I get banding.

1. Is that normal? I mean the original TV gammas are not even close to any gamma 2.2, 2.4 or BT.1886.

2. I was thinking about BT.1886 because most of my videos are to be seen on TV or Internet. What about using a different gamma as 2.5 or 2.6? No matter what I change I can't get any close to those gamma powers (banding gets visible in the shadows).

Any thoughts?

Thank you.
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post #2 of 27 Old 09-25-2018, 07:07 PM
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I don't have an answer for you, but on the same topic, I wonder if I'm doing something wrong with HCFR. I haven't used it in 5 years or so, but I'm trying to calibrate my LG OLED77C8 using an i1Display Pro.


I was feeling good about my grayscale tracking, but then I looked at the gamma curve. This is with the TV set to BT.1886, which should be about 2.4. So how am I measuring 1.9? There isn't a higher setting on the TV to try. I must be doing something wrong here...right?
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post #3 of 27 Old 09-28-2018, 07:52 AM - Thread Starter
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@eelton

Looks like your reference gamma in HCFR is a 2.4 power curve, not BT. 1886. In HCFR MENU Advanced - Preferences - References check if ITU-R BT.1886 is checked instead of Display gamma (power law) of 2.4.

Quote:
it is important to note that BT. 1886 (= 2.4 absolute gamma, black output offset 0%) is not the same as a 2.4 power curve – it takes into account the black level (and white level) of the display, thus in practice the overall gamma may end up closer to 2.2 than 2.4, as you have observed. BT. 1886 will only match a 2.4 power curve if the display black level is zero (e.g. OLED).
Does your TV have any other gamma settings or multi-point gamma? You could play with your contrast and brightness value to see if it has any effect on gamma, because sometimes "Contrast" also affects gamma not only the WhitePeak.

Best regards.
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post #4 of 27 Old 09-28-2018, 08:32 AM
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Thanks for the reply.


The setting in HCFR was "Display Gamma (black compensation)." I changed it to ITU-R BT.1886; the gamma curve is still at 1.95 with the TV's setting on BT.1886 (or 2.4, which looks the same on my OLED TV).


I tried lowering the contrast from 80 to 40 as a test, but the gamma stayed the same. When I lowered the brightness from 60 to 50, though, the gamma curve came up to 2.1.


This leads me to wonder about how I had set the brightness. I had used a black screen and brought up the brightness until there was the start of a glow to the screen, then backed off a notch (that was 60). But if I use the pattern with flashing near-black bars, I can see #17 flashing at 50.
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Quote:
Originally Posted by eelton View Post
Thanks for the reply.


The setting in HCFR was "Display Gamma (black compensation)." I changed it to ITU-R BT.1886; the gamma curve is still at 1.95 with the TV's setting on BT.1886 (or 2.4, which looks the same on my OLED TV).


I tried lowering the contrast from 80 to 40 as a test, but the gamma stayed the same. When I lowered the brightness from 60 to 50, though, the gamma curve came up to 2.1.


This leads me to wonder about how I had set the brightness. I had used a black screen and brought up the brightness until there was the start of a glow to the screen, then backed off a notch (that was 60). But if I use the pattern with flashing near-black bars, I can see #17 flashing at 50.
Keep it at 50.
With OLED BT.1886 is the same as 2.4 since you’re getting perfect black.
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post #6 of 27 Old 09-28-2018, 11:02 AM
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What panasonic tv model?

Panasonic 42inch ST60 owner
Panasonic 42inch S10 ES (Europe/Silver) owner
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post #7 of 27 Old 09-28-2018, 02:17 PM
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Do not ever use the brightness control to adjust the gamma.

The default brightness setting on that vintage of plasma is 58 (If I remember correctly).

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post #8 of 27 Old 09-30-2018, 03:06 AM - Thread Starter
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Quote:
Originally Posted by Gregg Loewen View Post
Do not ever use the brightness control to adjust the gamma.

The default brightness setting on that vintage of plasma is 58 (If I remember correctly).
Quote:
Some displays have Brightness/Contrast (and possibly Backlight) controls that do not function as expected, with Brightness acting more like Backlight, and Contrast just setting the peak clipping levels at any white level, with no direct 'Black Level' control.


I have a TV with no gamma adjustments at all. How I suppose to adjust gamma? Amy hints?
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post #9 of 27 Old 09-30-2018, 06:48 AM
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you select a different preset mode (Sports, vs Cinema vs custom). you then look for a gamma preset.

That is all you can do to adjust gamma (if your display does not have other controls).

Brightness control is set independently of the gamma, as is Contrast.

If you are then not happy with the image consider an outboard video processor like a Lumagen or a LUT box like the EEColor.

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post #10 of 27 Old 09-30-2018, 07:50 AM
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Quote:
Originally Posted by qqqavi View Post
Hi everyone,

I've been using HCFR to calibrate my Panasonic TV and the results are good, however the gamma is way too off compared to the BT.1886 reference or any gamma reference like 2.2, 2.4, etc . In the image attached (gamma.jpg), you can see the results:
Hi, what display model of Panasonic you are trying to calibrate?

You have measure 0.067 nits black level.

What way you are using to display patterns for measurements to your display?

Have you checked contrast/brightness flashing bars patterns before starting your measurements?

Select a Professional picture mode, reset your calibration controls (disable picture enhancements) and see with default display settings (contrast/brightness) which flashing bars you see.

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post #11 of 27 Old 09-30-2018, 07:58 AM
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Quote:
Originally Posted by qqqavi View Post
I've been using HCFR to calibrate my Panasonic TV and the results are good, however the gamma is way too off compared to the BT.1886 reference or any gamma reference like 2.2, 2.4, etc . In the image attached (gamma.jpg), you can see the results:

1. Is that normal? I mean the original TV gammas are not even close to any gamma 2.2, 2.4 or BT.1886.
Quote:
Originally Posted by eelton View Post
I don't have an answer for you, but on the same topic, I wonder if I'm doing something wrong with HCFR. I haven't used it in 5 years or so, but I'm trying to calibrate my LG OLED77C8 using an i1Display Pro.

I was feeling good about my grayscale tracking, but then I looked at the gamma curve. This is with the TV set to BT.1886, which should be about 2.4. So how am I measuring 1.9? There isn't a higher setting on the TV to try. I must be doing something wrong here...right?
Hi guys,

I see that you have both configure your HCFR to not include to the reported dE gamma errors, from HCFR Preferences -> Advanced -> change the Grayscale handling to ''Absolute Y w/gamma'', to include to the dE calculation the gamma errors also. (Color Difference Formula from Recommend to CIE2000)

Look at each % Grey data the meter reports, there is a Y (which shows to you the measured luminance) and the Y target (which show the target luminance), and re-adjust your settings to fix gamma errors also.

Before starting the grayscale adjustments, take a 21-Point Grayscale run measuring all display available gamma presets, then view the reports and choose to work with the one that you see that is measures closer to your target gamma (so you save time from less adjustments which will be required to fix the issues later).

Do the same test with colorspace preset (taking 4-Point Saturation sweeps....choose the one that has better tracking of REC.709) and do the same with Color Temp preset (taking 21-Point Grayscale....choose the one that has less RGB errors in average, to see which mode is closer to D65).

When you will find all these, you will do contrast/brightness/color clipping check via patterns and after that you will start to calibrate your grayscale. Start with 2-Point RGB balance and do 100% White with RGB-Gain and 30% Gray with RGB-Offeset controls, when you will do many back/forth until you have stable readings, you will move to 10-Point RGB balance, after your are ready with grayscale you will move to CMS calibration.

When you will start with 100% White, keep one of the R or G or B at zero position and reduce values from other 2 controls, while to handle your luminance output (nits) you will use the backlight (not the RGB balance controls).

If you have 10-Point RGB balance controls, its better idea to use 21-Point Grayscale patterns, its better for detecting un-align of calibration controls adjustments with displayed xx% patterns.

Also a good approach is to not perform static pattern real-time (with TV menus active, that can affect your measurements), but to run a complete grayscale sweep and then look your charts and apply at once all the settings per each control you believe that will fix (reduce) the errors, then run a new grayscale sweep and you will see that your errors will be lower now, then repeat-repeat until the results will be good.

After the end of grayscale you will move to CMS calibration, after the end of CMS cal, re-check grayscale again.

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post #12 of 27 Old 09-30-2018, 08:06 AM
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Quote:
Originally Posted by eelton View Post
I tried lowering the contrast from 80 to 40 as a test, but the gamma stayed the same. When I lowered the brightness from 60 to 50, though, the gamma curve came up to 2.1.

This leads me to wonder about how I had set the brightness. I had used a black screen and brought up the brightness until there was the start of a glow to the screen, then backed off a notch (that was 60). But if I use the pattern with flashing near-black bars, I can see #17 flashing at 50.
Hi, to set your brightness and contrast, you have to use flashing bars patterns.

How you are generating your color patterns right now for your measurements?

What is your measured black/white levels? If you have mismatch of levels (between video legal/data level) then you can have wrong measured gamma.

About some near black evaluation (to see what gamma preset) provides better near black gamma tracking, or how a Brightness setting affects near black, I have posted some details about what tests users can perform here: https://www.avsforum.com/forum/139-d...l#post56738984

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post #13 of 27 Old 09-30-2018, 09:36 AM
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Quote:
Originally Posted by ConnecTEDDD View Post
Hi, to set your brightness and contrast, you have to use flashing bars patterns.

How you are generating your color patterns right now for your measurements?

What is your measured black/white levels? If you have mismatch of levels (between video legal/data level) then you can have wrong measured gamma.

About some near black evaluation (to see what gamma preset) provides better near black gamma tracking, or how a Brightness setting affects near black, I have posted some details about what tests users can perform here: https://www.avsforum.com/forum/139-d...l#post56738984
Thanks for the information.

I used the flashing bars pattern on the AVS HD 709 disc to set the black level (17 and higher flashing).

I have displayed test patterns (A) from AVS, stored on my TiVo, measured with HCFR, (B) from AVS, stored on a networked computer and played through the TV's Plex app, measured with HCFR, (C) from AVS, via my laptop with an HDMI connection using your Lightspace software and a floating window; and (D) generated by HCFR via Chromecast, measured with HCFR.

I've attached images for gamma curves. A and B produced identical results, showing a nearly flat gamma curve at 2.02. D produced a slightly less flat curve, with an average of 2.25. The gamma curve from C showed my gamma to be below the 2.4 goal, although I'm not sure how to tell by how much from the graph. I've also attached the table showing the levels in HCFR, from trial D. All of these measurements were with the same settings on the TV (including gamma BT.1886) in ISF dark room mode.

At any rate, all of my other results are where they should be, and I'm happy with the image. I'll chose to use think of the gamma as the Chromecast result of 2.25, so that it doesn't seem way off.
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post #14 of 27 Old 09-30-2018, 12:44 PM
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Quote:
Originally Posted by eelton View Post
Thanks for the information.

I used the flashing bars pattern on the AVS HD 709 disc to set the black level (17 and higher flashing).
Ok, so all bars in contrast/brightness seem the same between A,B?

Quote:
Originally Posted by eelton View Post
I have displayed test patterns (A) from AVS, stored on my TiVo, measured with HCFR, (B) from AVS, stored on a networked computer and played through the TV's Plex app, measured with HCFR, (C) from AVS, via my laptop with an HDMI connection using your Lightspace software and a floating window; and (D) generated by HCFR via Chromecast, measured with HCFR.
LightSpace is not my software, just I named Ted's LightSpace my calibration disk, which is universal calibration disk (work with CalMAN/ChromaPure/HCFR additionally) but the main and most content of disk is for 3D LUT profiling via LightSpace, displaying thousand colors without user prompt for 3D LUT with LightSpace.

What is the output settings of your TiVo? (YCbCr?)

When you are using a notebook with extended desktop with software generator (LightSpace/HCFR etc.), the notebook/software settings are affecting the accuracy.

Most of the times, users find very easy and quick solution to use their Notebook/PC HDMI output for patch generation using CalMAN's software pattern generator, but without doing proper testing to see if their output is correct, there level mismatch (confusing video/PC levels), some will find out their mistake at the end of their calibration but they will have wasted already so much time, because the output was not correct, some will never notice anything since they will have as a proof the colorful charts of CalMAN where they will see that all are fine and they have low average dE.

At the end of the day, you need to have accurate colors from the source you are using to playback the movies, not from other untested solution.

For example, stand-alone players can have accurate YCbCr output while Notebook PC's can have accurate RGB output, some TV's are handling differently the signal when you send RGB or YCbCr, usually they convert the incoming RGB signal to YCbCr for processing, there other TV's which handle differently the 60p from 24p input, all these require some testing to find out what is happening.

To see if your Notebook/PC HDMI RGB output is configured correctly you have to compare it using a stand-alone player output (configured to output YCbCr, because most of the players are bit-perfect at that colorspace output) and using a calibration disk compatible with HCFR being used as reference. (Setting the PC/Notebook to output YCbCr is not recommended, because it will be required specific 3x3 matrix to convert RGB-Video to REC.709 YCbCr)

You need to compare Grayscale and gamut (saturation or colorchecker measurement runs) from both patch solution to see if you have agreement, if you have agreement then you can use your Notebook/PC HDMI for patch generation (using HCFR software generator), see also your reported black/white level and gamma measurements. Not all notebooks can be used as software patch generators, there video card settings, Windows ICC or VCGT which can affect the accuracy of the HDMI output. Having a stand-alone player with a bit-perfect calibration disk, you can use it as reference point for that test.

To be sure that the Video Card or OS is not altering your HDMI Output accuracy, you have to check your Video Card panel settings and disable any dynamic mode or other enhancement, then remove any ICC profile you will see to your Control Panel -> Color Management and finally resetting your VCGT (Video Card Gamma Table).

Also your software patch generator has been configured to output correct levels, ideally you need to set HCFR to output video levels (16-235), VGA (0-255) and TV to expect 16-235.

For grayscale only you can use AVSHD grayscale (when you will have enable the software offset to fix levels mismatch of AVSHD with HCFR (see details here), but for gamut measurements (for example 4-Point Saturation sweep), AVSHD is not compatible with all colors of HCFR 4-Point Saturations (and there no fix about this), for example:

AVSHD 50% Red Saturation Pattern has RGB Triplet 190.95.95 but HCFR's Color Engine needs/calculates errors from RGB Triplet 191.96.96, it's 0.42 dE2000 error.

AVSHD 75% Magenta Saturation Pattern has RGB Triplet 203.100.203 but HCFR's Color Engine needs/calculates errors from RGB Triplet 202.99.202, it's 0.36 dE2000 error.

When you performing such comparisons you have to match the size of the patterns you are using.

Quote:
Originally Posted by eelton View Post
I've attached images for gamma curves. A and B produced identical results, showing a nearly flat gamma curve at 2.02. D produced a slightly less flat curve, with an average of 2.25. The gamma curve from C showed my gamma to be below the 2.4 goal, although I'm not sure how to tell by how much from the graph. I've also attached the table showing the levels in HCFR, from trial D. All of these measurements were with the same settings on the TV (including gamma BT.1886) in ISF dark room mode.

At any rate, all of my other results are where they should be, and I'm happy with the image. I'll chose to use think of the gamma as the Chromecast result of 2.25, so that it doesn't seem way off.
Its unknown which of those is the most accurate, when you don't access to a reference generator to have as reference to test all other patch playback/generator solutions, one way is use your TV USB to playback from there the Media Files and have this as reference, if there not available stand-alone blu-ray/media player of known brand, then measure grayscale and color gamut patterns and see which option is tracking better your 'reference'.

If you perform these test, upload all measurement data.

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post #15 of 27 Old 09-30-2018, 01:28 PM
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Yes, I became painfully aware of the issues when using a laptop for test image generation. It eventually seemed to work when I used the Intel HD graphics control panel to set it for YCbCr, limited range, and color correction off. Having said that, I only used this method for my LightSpace trials; everything with HCFR was Plex, TiVo, or Chromecast. The TiVo (Roamio) output is via HDMI. I don't see any video output setting that would affect color. Overall, I like using the TiVo as the image source, as I do most of my viewing through that device.

Thanks for pointing out the slight mismatch between AVSHD and HCFR (although the HCFR option for "use round down levels (AVSHD, DVE)" in the paged you linked to is greyed out for me).

Once I discovered I could use Chromecast with HCFR and have everything automated, it was a revelation. So, hopefully that is an accurate way of approaching it. For what it's worth, my greyscale tracking and color gamut looked essentially the same between Chromecast and either Plex or TiVo sourced patterns (Chromecast and Plex results attached). I don't own a Blu-ray player, so I don't have that as an option as a source.
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post #16 of 27 Old 09-30-2018, 01:56 PM
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Quote:
Originally Posted by eelton View Post
Yes, I became painfully aware of the issues when using a laptop for test image generation. It eventually seemed to work when I used the Intel HD graphics control panel to set it for YCbCr, limited range, and color correction off. Having said that, I only used this method for my LightSpace trials; everything with HCFR was Plex, TiVo, or Chromecast. The TiVo (Roamio) output is via HDMI. I don't see any video output setting that would affect color. Overall, I like using the TiVo as the image source, as I do most of my viewing through that device.
If you start a new HCFR session and select as generator selection 'DVD Manual', then it will be not grayed out that setting.

Quote:
Originally Posted by eelton View Post
Thanks for pointing out the slight mismatch between AVSHD and HCFR (although the HCFR option for "use round down levels (AVSHD, DVE)" in the paged you linked to is greyed out for me).

Once I discovered I could use Chromecast with HCFR and have everything automated, it was a revelation. So, hopefully that is an accurate way of approaching it. For what it's worth, my greyscale tracking and color gamut looked essentially the same between Chromecast and either Plex or TiVo sourced patterns (Chromecast and Plex results attached). I don't own a Blu-ray player, so I don't have that as an option as a source.
Your gamut tracking of Cyan not look so good, probably related to AVSHD saturation mismatch, need further testing.

No problem if you don't have blu-ray player as source, the most important is to have accurate colors when you will watch content from your sources, for that reason (when you are not using your exact sources for patch generation) you need to test/compare if that are matching.

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post #17 of 27 Old 10-01-2018, 07:40 PM
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I decided to try using HCFR's greyscale with gamma graph and the TV's 20 point greyscale adjustment to see if I could get to a gamma of 2.4 by what felt like brute force. I ended up with 2.39; the gamma goes up at the top end for reasons that are unclear to me (since the luminance response looks on target and the greyscale w/gamma curve is flat there...obviously there is a lot I don't understand about this stuff).

I calibrated the colors for 100%, but my saturation sweeps (especially yellow and green) are a disaster--I assume because of that brute force aspect, using large color adjustments. Yes, this still needs work.
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post #18 of 27 Old 10-01-2018, 10:13 PM
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Originally Posted by eelton View Post
I decided to try using HCFR's greyscale with gamma graph and the TV's 20 point greyscale adjustment to see if I could get to a gamma of 2.4 by what felt like brute force. I ended up with 2.39; the gamma goes up at the top end for reasons that are unclear to me (since the luminance response looks on target and the greyscale w/gamma curve is flat there...obviously there is a lot I don't understand about this stuff).
Gamma is very sensitive to level errors at high IREs. A Y-value that's 1% too low, which is hardly noticeable on the luminance graph and greyscale w/gamma graph, will make gamma jump from 2.4 to 2.6. There's no real significance to that, although one could be monitoring the gamma curve while while adjusting the 20-point greyscale.

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I calibrated the colors for 100%, but my saturation sweeps (especially yellow and green) are a disaster--I assume because of that brute force aspect, using large color adjustments. Yes, this still needs work.
In many cases 75%/75% works better than 100%.

Last edited by Dominic Chan; 10-02-2018 at 05:18 AM.
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post #19 of 27 Old 10-02-2018, 12:53 AM
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Originally Posted by Dominic Chan View Post
Gamma is very sensitive to level errors for high IREs.
Yep. Gamma is not a perceptually uniform measurement. Delta E's are much closer to being perceptually uniform.
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post #20 of 27 Old 10-02-2018, 08:27 AM - Thread Starter
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Originally Posted by ConnecTEDDD View Post
Hi guys,

I see that you have both configure your HCFR to not include to the reported dE gamma errors, from HCFR Preferences -> Advanced -> change the Grayscale handling to ''Absolute Y w/gamma'', to include to the dE calculation the gamma errors also. (Color Difference Formula from Recommend to CIE2000)

Look at each % Grey data the meter reports, there is a Y (which shows to you the measured luminance) and the Y target (which show the target luminance), and re-adjust your settings to fix gamma errors also.

Before starting the grayscale adjustments, take a 21-Point Grayscale run measuring all display available gamma presets, then view the reports and choose to work with the one that you see that is measures closer to your target gamma (so you save time from less adjustments which will be required to fix the issues later).

Do the same test with colorspace preset (taking 4-Point Saturation sweeps....choose the one that has better tracking of REC.709) and do the same with Color Temp preset (taking 21-Point Grayscale....choose the one that has less RGB errors in average, to see which mode is closer to D65).

When you will find all these, you will do contrast/brightness/color clipping check via patterns and after that you will start to calibrate your grayscale. Start with 2-Point RGB balance and do 100% White with RGB-Gain and 30% Gray with RGB-Offeset controls, when you will do many back/forth until you have stable readings, you will move to 10-Point RGB balance, after your are ready with grayscale you will move to CMS calibration.

When you will start with 100% White, keep one of the R or G or B at zero position and reduce values from other 2 controls, while to handle your luminance output (nits) you will use the backlight (not the RGB balance controls).

If you have 10-Point RGB balance controls, its better idea to use 21-Point Grayscale patterns, its better for detecting un-align of calibration controls adjustments with displayed xx% patterns.

Also a good approach is to not perform static pattern real-time (with TV menus active, that can affect your measurements), but to run a complete grayscale sweep and then look your charts and apply at once all the settings per each control you believe that will fix (reduce) the errors, then run a new grayscale sweep and you will see that your errors will be lower now, then repeat-repeat until the results will be good.

After the end of grayscale you will move to CMS calibration, after the end of CMS cal, re-check grayscale again.
Thanks. I'll try that.
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post #21 of 27 Old 10-02-2018, 08:01 PM
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Hey ConnecTEDDD

I have always calibrated REC709 75% black compensated (with or without actually noting and checking the box) with generator set to 0-255 regardless of wether I run full or limited output from my PC. I also check off W/O GAMMA for my RGB, and end result is around 0.17-0.19 white dE and 2.2 flat gamma overlapping the reference 2.2 line.

When I turn on my local dimming, my gamma line starts at 2.3 and ends at like 1.6 or something, and gamma drops from 2.2 to something like 1.9-2.0 average.. The greyscale w/o gamma is still a happy 0.30 or so, but the gamma yellow line confuses me. Is W/O GAMMA the correct way to adjust my REC709 2.2 TV set, or is WITH GAMMA correct? If I switch to WITH gamma i'll have to raise a lot of my 10-40% levels to get back on the RGB line.

Paul

Last edited by Anderegg; 10-02-2018 at 08:06 PM.
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post #22 of 27 Old 10-02-2018, 09:15 PM
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Is W/O GAMMA the correct way to adjust my REC709 2.2 TV set, or is WITH GAMMA correct? If I switch to WITH gamma i'll have to raise a lot of my 10-40% levels to get back on the RGB line.
You should get the same end result whether you use RGB with or without gamma, but in the latter case you also need to keep an eye on the gamma curve.
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post #23 of 27 Old 10-02-2018, 09:26 PM
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Originally Posted by Dominic Chan View Post
You should get the same end result whether you use RGB with or without gamma, but in the latter case you also need to keep an eye on the gamma curve.
Would this be understood better that if I calibrate to WITH gamma, the w/o gamma switch would look correct, but not so for the opposite?

Paul
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post #24 of 27 Old 10-02-2018, 09:44 PM
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Would this be understood better that if I calibrate to WITH gamma, the w/o gamma switch would look correct, but not so for the opposite?

Paul
Yes, calibrating to “RGB with gamma” means both RGB and gamma are correct, whereas “RGB without gamma” only ensures RGB is correct. That’s why in the latter case you need to keep an eye on the gamma curve in addition to RGB, or equivalently, make sure Y=Target-Y. As long as you’re doing this, the two approaches will give you the same end results, i.e., both RGB and gamma will be correct.

Last edited by Dominic Chan; 10-02-2018 at 10:01 PM.
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post #25 of 27 Old 10-02-2018, 10:30 PM
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Perfect, I just spent the last hour recalibrating to black compensated 2.2 with gamma, got to 0.24dE, then switch the view to w/o gamma, and the gamma looked the same, and the dE went down to 0.22dE, so your advice proved completely sound, and I feel more confident about my calibration now. WITH gamma really is a PITA though...I guess I got used to w/o after playing abound with BT1886...simpler and easier to get good "numbers", but apparently in the end not as accurate.

Paul

Quote:
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Yes, calibrating to “RGB with gamma” means both RGB and gamma are correct, whereas “RGB without gamma” only ensures RGB is correct. That’s why in the latter case you need to keep an eye on the gamma curve in addition to RGB, or equivalently, make sure Y=Target-Y. As long as you’re doing this, the two approaches will give you the same end results, i.e., both RGB and gamma will be correct.
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post #26 of 27 Old 05-20-2019, 07:50 PM
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Originally Posted by qqqavi View Post
I have a TV with no gamma adjustments at all. How I suppose to adjust gamma? Amy hints?
Have you entered the service code to access the advanced adjustments menu?
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post #27 of 27 Old 05-20-2019, 09:06 PM
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Deleted - wrong thread.

Last edited by Nordo; 05-21-2019 at 12:59 AM.
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