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post #4141 of 4593 Old 12-25-2015, 05:41 AM
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Quote:
Originally Posted by seiyafan View Post
Correct me if I am wrong, the tone curve under calibration and 3d lut are independent of each other.
Correct.

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post #4142 of 4593 Old 12-26-2015, 08:44 AM
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Originally Posted by naththo View Post

I feel I need to upgrade from Spyder4Elite to Calman C3 or C6 with Enthusiast set for tv and monitor for computer. So that'll be good. Although I think that I buy C6 is better off, so it can measure any thing like TV, Monitor, OLED, projector whereas C3 has more limit to it. C6 is $695 USD though. This will measure a lot more accurate than old Spyder4 for sure.
I haven't used an C3 or C6 but I think it overpriced (but maybe the price of software is already included).
What has been always suggested: buy an i1 Display Pro (new or used) http://www.xrite.com/i1display-pro and rent/buy a used colormunki or i1pro spectorphotometer.
After that, as fhoech said, you can create a correction matrix (e.g. with dispalGUI) with the i1pro for the i1DisplayPro and the given display. That will give you the best result. (I happen to have 2 i1pro if you are living in Europe.)

Ah, I am from Australia apparently. I found they have bundle value pack that Calman offered which is great it is bundled with software.

CalMAN Enthusiast with SpectraCal C6-R $599.00 R = Refurbished but still same performance as brand new C6 though. Software itself worth $399 and brand new itself C6 is $695. If I want brand new C6 bundled with software I would have to pay $999. So no point on that. I go for the bundled that is offered good price. Also C6 comes with NIST so it is not cheap at all. NIST is expensive. But unfortunately exchange rate has not been nice. So only option I could do is i1 display pro one for the time being or get this CalMAN Home Express TV Calibration Kit for $99 from Amazon but can't get it till next pay which is next week I believed it will already be out of stock by then. $149 will be normal price afterward then I can upgrade to Ethusaist later on. As long if exchange rate improves. Lots of buyer in Australia avoid online purchase when exchange rate is very bad. It cost 2 times more expensive. Exchange rate people are greedy.
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post #4143 of 4593 Old 12-26-2015, 01:05 PM
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@fhoech


Florian, I have a question regarding something that Chad suggested:


"I have found that calibrating the M series with local dimming off is best, but it's beneficial to compensate for the fact that turning LD on again will darken shadow detail. It's unconventional, but using BT1886 and specifying a black level of .01 fL for night mode or .02 fL for day mode (may vary a little bit depending on your light output targets) will compensate nicely for the LD darkening the shadow detail."


How would I go about doing that in dispcalGUI? I can tell you that with my current settings on the TV and leaving pretty much everything in dispcalGUI at defaults for a madVR calibration, I get a black level of 0.027 cd/m2 (0.007 fL).
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post #4144 of 4593 Old 12-27-2015, 05:06 AM
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Just played with tone curve for 3d lut a bit, I found out with a 5% black offset it can bring gamma to 2.4 but with 0% black offset it has difficulty to achieve anything higher than 2.3. This should be caused by the nonzero black level of the monitor right?
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post #4145 of 4593 Old 12-27-2015, 05:23 AM
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Alright I need to ask a very serious question:

How MUCH better in accuracy is i1 Display Pro over against Spyder4Elite? Cos I am very concern about how they ship the product with or without NIST certification. Without certification we don't know if the device is accurate or not and we end up with more DE error.

I am still deciding whether to get Calman C6 but too expensive so thinking of i1 Display Pro but that question above is still a question that need to be answered.
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post #4146 of 4593 Old 12-27-2015, 05:42 AM
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Quote:
Originally Posted by naththo View Post
How MUCH better in accuracy is i1 Display Pro over against Spyder4Elite? Cos I am very concern about how they ship the product with or without NIST certification. Without certification we don't know if the device is accurate or not and we end up with more DE error.

I am still deciding whether to get Calman C6 but too expensive so thinking of i1 Display Pro but that question above is still a question that need to be answered.
I can't tell you how accurate they are but I heard from users that e.g. the spider3 had serious errors in black measurement (although the spider4/5 can be totally different). But there's a thing: the spiders, i1DisplayPro and C6 are all colorimeters! That means no matter how accurate they are on paper they won't be accurate without a spectrophomometer (e.g. i1pro) correction! You can also search the net for reviews about them.
And I definitely wouldn't pay that amount of money for a refurbished equiptment.
I think you think too much Just go for the i1DisplayPro amongst them and you won't make a mistake. (You'll see later than the whole process is way more complicated and you can screw up couple of places even if you have the best colorimeter )
Quote:
Originally Posted by VBB View Post
"I have found that calibrating the M series with local dimming off is best, but it's beneficial to compensate for the fact that turning LD on again will darken shadow detail. It's unconventional, but using BT1886 and specifying a black level of .01 fL for night mode or .02 fL for day mode (may vary a little bit depending on your light output targets) will compensate nicely for the LD darkening the shadow detail."

How would I go about doing that in dispcalGUI? I can tell you that with my current settings on the TV and leaving pretty much everything in dispcalGUI at defaults for a madVR calibration, I get a black level of 0.027 cd/m2 (0.007 fL).
Which software did he use? I can see a similar setting in HCRF (Advanced menu -> Preferences -> References -> Display gamma with black compensation) but I didn't find the corresponding switch(es) of Argyll command line utils.
But: are you talking about elevating the shadows in the lower part of the luminance scale? If yes then I'm not sure that it'll work for you.

Quote:
Originally Posted by seiyafan View Post
Just played with tone curve for 3d lut a bit, I found out with a 5% black offset it can bring gamma to 2.4 but with 0% black offset it has difficulty to achieve anything higher than 2.3. This should be caused by the nonzero black level of the monitor right?
Yes, but I don't understand why I'll make a detailed post about this later today, 'cause I figured it out how it works.

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post #4147 of 4593 Old 12-27-2015, 10:41 AM
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Quote:
Originally Posted by chros73 View Post
Which software did he use? I can see a similar setting in HCRF (Advanced menu -> Preferences -> References -> Display gamma with black compensation) but I didn't find the corresponding switch(es) of Argyll command line utils.
But: are you talking about elevating the shadows in the lower part of the luminance scale? If yes then I'm not sure that it'll work for you.
I can only assume that Chad means to use a fixed black level that is higher than the measured one. This would then make the low end brighter to compensate for the dimming. I'm sure this can be set in dispcalGUI, I just don't know where exactly.
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post #4148 of 4593 Old 12-27-2015, 01:07 PM
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Dear all,

I finally find a solution concerning my problem with blacks lisibility below 5%.
To reminder, when I calibrate my projector with my i1d3 and DispCalGUI+Argyll, I always loose the blanking bar 17 when I check the mapping/grayscale.
I have the problem with 2.4 gamma or BT.1886. Since my i1D3 can't read my 100% black (no value below 3%), my gamma curve is always linear (read my previous posts for more details).

I was searching for a solution to correct the gamma curve below 3% and finally I found a "videoequalizer/gamma editor" script writed in pixel shaders by Emmanuel Piat (very well known on french forums).
If you are like me, using an htpc, you can easily combinate the 3dlut and this pixel shaders gamma correction with mpc-hc/mpc-be to make a little modification on the gamma curve at very low ires.
It's very simple to use and to parametrize it. You just decrease the gamma at this low ires until the blanking bars become visible again.
By this way, you can have a very good grayscale with your i1d3 and displays with a very good on/off CR.

I translated what Emmanuel said about the script:

Hello,

here's a pretty basic code for a video equalizer implemented in PS.
You can easily adapt the code to put as much control point you want.
Interpolation is linear between each point so it remains basic but generally sufficient for light corrections.
I have not optimized the code to gain visibility.

You have to define control points l1, l2, l3, etc. in a range between 0 and 255 (in entries).
The corresponding "d" corrections are vertical offsets relative to a linear output.
It means that for each control point, you have:
out = in + d
Between control points, interpolation output level is linear.

Before this adjustment, you can make a conventional gamma correction adjusting the gamma settings.
This is usually as it is implemented on projectors that allow gamma coefficient adjustment followed by a fine adjustment by video equalizer to fine-tune the output levels.

This pixel shader have to be put at the end of the video chain and is adapted to only output level between 0 and 255 (hdmi extended).

Note that the program would be easily adaptable to a 1D-LUT correction grayscale ... Just add independent adjustments for each channel instead of having identical corrections.


And now the code:

Code:
// Basic VideoEqualizer with linear interpolation

sampler s0 : register(s0);
float4 p1 : register(c1);

// Gamma correction relative native display gamma
#define gamma 1.0

// Five ix control points between 0-255 (you can add/remove/modify points as much as you want)
// All dx values are set to 1 by default. Simply increase those values
#define l1 1
#define d1 1

#define l2 2
#define d2 1

#define l3 3
#define d3 1

#define l4 4
#define d4 1

#define l5 5
#define d5 1

float4 main( float2 tex : TEXCOORD0 ) : COLOR
{   float4 color;
   float g1, g2, g3, g4, g5;
   float o1, o2, o3, o4, o5;

   color = pow(tex2D(s0, tex),gamma);
   
   g1 = 1.0*l1/255;   o1 = 1*d1/255;	//1
   g2 = 1.0*l2/255;   o2 = 1*d2/255;	//2
   g3 = 1.0*l3/255;   o3 = 1*d3/255;	//3
   g4 = 1.0*l4/255;   o4 = 1*d4/255;	//4
   g5 = 1.0*l5/255;   o5 = 1*d5/255;	//5
            
// Red treatment     
   if (color.r <= g1) color.r = (g1+o1)/g1*color.r;
  else if (color.r <= g2) color.r = ((g2-g1+o2-o1)*color.r + o1*g2-o2*g1)/(g2-g1);
  else if (color.r <= g3) color.r = ((g3-g2+o3-o2)*color.r + o2*g3-o3*g2)/(g3-g2);
  else if (color.r <= g4) color.r = ((g4-g3+o4-o3)*color.r + o3*g4-o4*g3)/(g4-g3);
  else if (color.r <= g5) color.r = ((g5-g4+o5-o4)*color.r + o4*g5-o5*g4)/(g5-g4);
  else color.r = ((1.0-g5-o5)*color.r + o5)/(1.0-g5);

// Green treatment
   if (color.g <= g1) color.g = (g1+o1)/g1*color.g;
  else if (color.g <= g2) color.g = ((g2-g1+o2-o1)*color.g + o1*g2-o2*g1)/(g2-g1);
  else if (color.g <= g3) color.g = ((g3-g2+o3-o2)*color.g + o2*g3-o3*g2)/(g3-g2);
  else if (color.g <= g4) color.g = ((g4-g3+o4-o3)*color.g + o3*g4-o4*g3)/(g4-g3);
  else if (color.g <= g5) color.g = ((g5-g4+o5-o4)*color.g + o4*g5-o5*g4)/(g5-g4);
  else color.g = ((1.0-g5-o5)*color.g + o5)/(1.0-g5);

// Blue treatment
   if (color.b <= g1) color.b = (g1+o1)/g1*color.b;
  else if (color.b <= g2) color.b = ((g2-g1+o2-o1)*color.b + o1*g2-o2*g1)/(g2-g1);
  else if (color.b <= g3) color.b = ((g3-g2+o3-o2)*color.b + o2*g3-o3*g2)/(g3-g2);
  else if (color.b <= g4) color.b = ((g4-g3+o4-o3)*color.b + o3*g4-o4*g3)/(g4-g3);
  else if (color.b <= g5) color.b = ((g5-g4+o5-o4)*color.b + o4*g5-o5*g4)/(g5-g4);
  else color.b = ((1.0-g5-o5)*color.b + o5)/(1.0-g5);
  
   return color;
}
Source: http://www.homecinema-fr.com/forum/m...t30057042.html

To use it it's very simple, just add this pixel shaders under mpc-HC/BE and then visualize the blanking bars and modify in live (Ctrl+P to activate/deactivate the PS - Ctrl+9 to modify) the script to adapt the "d" corrections coefficients until the bars become visible again.

@madshi
As this script is writted in pixel shaders, maybe you can propose it in madvr (with some adjustements)? it would be great...

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post #4149 of 4593 Old 12-27-2015, 01:30 PM
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This looks like the simplest form of bilinear equalizer, which is fine, but not really the highest possible quality. I would like an equalizer to use some form of curve to do adjustments, instead of using bilinear steps. Anyway, the problem is not the algorithm, I can do that myself, the problem is that I simply have many other things to do which at the moment are more important to a bigger number of users.
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post #4150 of 4593 Old 12-27-2015, 01:35 PM
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Hello madshi

Yes of course I understand.
Maybe one day... I think that a lot of people will be interested by a gamma editor in madvr.
As Emmanuel said, it's a basic interpolation but sufficient in my many case.

Hope you had a nice christmas and thanks again for all you hard work on madvr!
++

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post #4151 of 4593 Old 12-27-2015, 02:05 PM
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Quote:
Originally Posted by VBB View Post
I can only assume that Chad means to use a fixed black level that is higher than the measured one. This would then make the low end brighter to compensate for the dimming. I'm sure this can be set in dispcalGUI, I just don't know where exactly.
You're right. I also couldn't find the option for this. Maybe this is the one for colprof: http://www.argyllcms.com/doc/colprof.html#B
You can add it at Options -> Set addinition command line arguments

Quote:
Originally Posted by Francois76l View Post
I finally find a solution concerning my problem with blacks lisibility below 5%.
Great find, thanks for letting it know!
Maybe the above option is also good for you. e.g. when we add a 0.01 cd/m2 to the zero black level and using 2.4 relative gamma with 100% output offset (at least HCFR says so).
Quote:
Originally Posted by madshi View Post
This looks like the simplest form of bilinear equalizer, which is fine, but not really the highest possible quality. I would like an equalizer to use some form of curve to do adjustments, instead of using bilinear steps. Anyway, the problem is not the algorithm, I can do that myself, the problem is that I simply have many other things to do which at the moment are more important to a bigger number of users.
That would be a real killer!

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post #4152 of 4593 Old 12-27-2015, 02:11 PM
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Quote:
Originally Posted by chros73 View Post
Great find, thanks for letting it know!
Maybe the above option is also good for you. e.g. when we add a 0.01 cd/m2 to the zero black level and using 2.4 relative gamma with 100% output offset (at least HCFR says so).
Thanks chros,
I already tested this solution (given by gwgill) before but it increases a little bit the black residual.
You should definitely try my solution, it works like a charm!

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post #4153 of 4593 Old 12-28-2015, 02:38 AM
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https://www.drycreekphoto.com/Learn/...nHardware.html

I have ordered i1 Display Pro today will be in next week. Will not buy Spyder again cos of inconsistent. I still have concern over accuracy since I calibrated on old panel that failed white balance test ie too green or too blue. The white 100% test they did not pass in that review link I post as they scored 4.2, too high DE. So this i1 Display Pro will do a lot better job definitely and 5 times faster, worth it for tv calibration and cut the time of calibration to shorter time and less plasma burn out will be better.
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post #4154 of 4593 Old 12-28-2015, 03:01 AM
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Quote:
Originally Posted by VBB View Post
I can only assume that Chad means to use a fixed black level that is higher than the measured one. This would then make the low end brighter to compensate for the dimming. I'm sure this can be set in dispcalGUI, I just don't know where exactly.
Ok, I think you mean this "Black level" setting on the calibration tab: http://dispcalgui.hoech.net/#settings_calibration_black_level
which is this http://www.argyllcms.com/doc/dispcal.html#B
The "problem" with this, since it's the first step during the whole process, you have to do the full calibration process again.

Can't this "-B" option of colprof be used to achieve the same result? If it can then it will be really useful for us to have this on the 3DLut page since we won't have to make new measurements.
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post #4155 of 4593 Old 12-28-2015, 02:35 PM
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Tone curve / gamma for beginners

A. Preface

1. This is the most misunderstood part (and not just regarding to calibration), otherwise the whole calibration process is pretty straightforward thanks to our beloved developers! So I decided to write a post about it that can be linked later on for newbies like me Please feel free to correct me at any point.
Actually it's pretty well documented (maybe too well, I've read them about 15 times in the last month but I'm still hesitating what they read ) in dispalGUI (although it belong to the calibration section, certain paragraphs still applies to the 3DLut creation) and Argyll documentation, but they're not for beginners.
http://dispcalgui.hoech.net/#trc
http://www.argyllcms.com/doc/collink.html#Ib
As it turned out you can easily get a grasp of it but you have to experiment a little bit. All we need to have is 1 more program and that is HCFR: it's simply amazing for this!

2. So we will talk about tone curve settings in dispalGUI (3DLUT tab), HCFR (Advanced menu -> Preferences -> References) and Argyll command line switch for collink.exe ( http://www.argyllcms.com/doc/collink.html#Ib ), they all do the same, but their settings can be confusing. These are the settings for Rec. 1886 with the 3 different programs:


- collink.exe switch: "-IB:0.0:2.4"
It's confusing a little bit, isn't it? We will understand them in B.3.

3. There are 2 main parts of this post: basics (B.) and a complete walkthrough with a given setup (C.).
At the end of this post you'll be able to make a pretty good educated guess which settings you want to apply for your 3DLUT generation after your first try.

B. Tone curve / gamma basics

1. Aim for a given gamma curve(s) that suit(s) your taste!

Yes, that's right. Read this amazing commentary about the different opinions of this topic (~10 minutes reading) : http://referencehometheater.com/2014...gamma-correct/
Let me quote the last 2 lines of it: "There is no incorrect choice for what gamma one should use when calibrating a display ... need to be aware of the reasoning behind a gamma choice, and the pros and cons of it."
There are lot of articles about gamma curve standard called Rec. 1886 and how they're happy about it. But still you can read that others prefer something different. It will turn out why in B.4.
Personally (I don't like to darken my viewing environment, I prefer the way as it it during the whole day), I agree with Vincent Teoh's opinion, I want to get a:
- for evening/night usage (with just a dim environment light on): 2.4 like gamma with slightly elevated shadows at the lower end of greyscale
- for cloudy day usage: 2.2 like gamma with slightly elevated shadows at the lower end of greyscale
- for sunny day usage: 2.2 like gamma with a little bit more elevated shadows at the lower end of greyscale

2. Choosing a different tone curve will change your colors!
It's not obvious at first (at least it wasn't for me). There's an animated gif in the middle of the above linked article that can show you this or you can easily test this:
- open up a previous project in HCFR (or just quickly make a new project and measure all the given colors (54 patches))
- select the color checker view
- modify the gamma value by selecting an another one on the reference page (don't forget to hit apply)
- you'll see the measurements errors changing!
That's why you can read about a lot of debate of choosing the correct gamma curve, since all we want to do is displaying the correct colors as it was intended.
But, since we don't know anything about how the current content was mastered, or even if we knew, our display setup will modify it anyway (see below)

3. Applying the same tone curve settings in both 3 programs
As we saw all the 3 refer to these settings differently. Documentation of Argyll command line switch for collink.exe ( http://www.argyllcms.com/doc/collink.html#Ib ) will help you understand these (you can look back at the pictures above).
dispalGUI calls technical as absolute and effective as relative, and it allows us to set the output offset not the input offset as HCFR does (0% output offset in dispalGUI equals to 100% input offset in HCFR (100-0=100)) . Also we only need to select ITU-R BT.1186 in HCFR (it's even more confusing, see it later).
a) Rec. 1886 (full (100%) input offset (BT.1886 like) with technical gamma of 2.4) in:
- Argyll: -IB:0.0:2.4 ("B" means technical = absolute)
- dispalGUI: 2.4 gamma, Absolute, 0% output offset
- HCFR: 0 Effective (=Absolute), 100% input offset
b) 2.2 gamma like (you'll see at B.4. why the 'like' word is here):
- Argyll: -Ib:1.0:2.2 ("b" means effective = relative)
- dispalGUI: 2.2 gamma, Relative, 100% output offset
- HCFR: 2.2 for Effective, 0% input offset
c) 2.4 gamma like:
- Argyll: -Ib:1.0:2.4 ("b" means effective = relative)
- dispalGUI: 2.4 gamma, Relative, 100% output offset
- HCFR: 2.4 for Effective, 0% input offset
d) if we would want to go for a 90% output offset with relative gamma of 2.37:
- Argyll: -Ib:0.1:2.37 ("b" means effective = relative)
- dispalGUI: 2.37 gamma, Relative, 90% output offset
- HCFR: 2.37 Effective, 10% input offset
It can be strange at first, but you get use to it when you try out different combinations. From now on I'll refer to the various gamma settings in the Argyll way (much easier to write them down) and you have to apply it to a certain program.

4. Black level of the display will change the selected tone curve!
That's right! I didn't know it either. And modifying it can be one of the key components with which you can modify your final tone curve.
You can see your current black level in:
- dispalGU: when you fire up a calibration and measure the "i" info section (in cd/m2)
- HCFR: e.g. at the Y row of 0 column of the gray scale view (with the xyY values)
And this black level can be changed depending on your needs: e.g. when you raise the brightness/backlight control on your display for day usage.
From the excellent Argyll documentation: ""

So let's take a look how the 3 usually used curves (gamma 2.2 like (-Ib:1.0:2.2), gamma 2.4 like (-Ib:1.0:2.4), Rec. 1886 (-IB:0.0:2.4)) would have been look like with different back levels.
If you want to try this out, you need HCFR again:
- create an empty project (even with the simulated meter)
- select gray scale view, select xyY values, enable the "editable data" beside of the view dropdown and enter the following black and white values (can be a setting for a LED TV during the day), the order is x,y,Y:
-- white (column 100): 0.312700 , 0.329000 , 120.00
-- black (column 0): 0.312700 , 0.329000 , 0.027
- then go take a look at the Gamma graph (Luminance graph can be also useful)
- change the gamma to different values in References (see A.2) then take a look again at the graphs
- raise or lower the black level (Y value of column 0 of gray scale view) and change the gamma then look at the graphs

a) If we would have perfect black (Y=0 cd/m2) the 3 curves would look like this:
-Ib:1.0:2.2 | -Ib:1.0:2.4 | -IB:0.0:2.4

These are called as pure power curves, they are linear.
Note that when we have a 0 black level then Rec. 1886 equals to 2.4 gamma pure power curve!

b) if we would have 0.027 cd/m2 black level (WLED panel):
-Ib:1.0:2.2 (gamma 2.2 like) | -Ib:1.0:2.4 (gamma 2.4 like) | -IB:0.0:2.4 (Rec. 1886)

And this is what happens in real life with gamma curves: black level will change the curve itself. We get lower gamma values at the lower part of the greyscale. Take a look how Rec. 1886 behaves, it provides a completely different curve from the rest: you'll get higher values at the higher end and lower gamma values at the lower end of greyscale.
About the first 2 image from Argyll documentation: "This is what many people think of as a "pure" power curve, even though this is not possible unless the display has a perfect zero black level." So we can call them as scaled 2.2/2.4 gamma curves.

c) if we would have 0.14 cd/m2 black level (CCFL IPS panel) - and it's a huge change in the black level - the change would be more drastic:
-Ib:1.0:2.2 (gamma 2.2 like) | -Ib:1.0:2.4 (gamma 2.4 like) | -IB:0.0:2.4 (Rec. 1886)

The lower end of the greyscale on the first 2 image is much lower then it was in the previous example!
And take a look at the Rec. 1886 curve! (the picture includes values between 2.3 and 1.9 !) You'll get an average gamma around 2.10 and very low values in the lower end and it won't go above 2.25! All because of the high black level of the display device! That curve maybe can be used during a sunny day in this case but definitely not during night! So that's why you can't say that this is the definite gamma curve, because differences in black level changes the resulting curve drastically. And there are lot of different displays out there.

5. Modifying the curve:
There are 3 options for this and we can mixed them together by setting them to:
- absolute or relative
- giving certain black output offset
- manually specifying (shifting) the black level itself
Let's assume that our black level is 0.027 cd/m2.

a) In the previous example (4.b.) we got curves really close to 2.2 and 2.4. Let's see what will happen if we lower the output offset with 10%. That means 90% output offset with an effective gamma 2.2 and 2.4 (we can't talk about Rec. 1886 anymore since we change the output offset from 0 !):
-Ib:1.0:2.2 (original) | -Ib:0.9:2.2 | -Ib:1.0:2.4 (original) | -Ib:0.9:2.4


With this setting we are lowering the values in the lower end of the grayscale without modifying much the higher end. So this setting is good for elevating shadow in the lower part of grayscale.
If you would apply the same 90% output but with a technical (absolute) gamma then the whole curve would move down resulting a little bit brighter overall image. (It seems I can set this in HCFR.)

b)
What would happen if we override the given black level of the display by specifying e.g. 0.034 cd/m2 instead? (I have to say that I don't know now where to specify this in dispalGUI only for the generated 3DLUT.)
-Ib:1.0:2.2 (original) | -Ib:1.0:2.2 with black 0.034 override

-Ib:1.0:2.4 (original) | -Ib:1.0:2.4 with black 0.034 override

-IB:0.0:2.4 (Rec. 1886 original) | -IB:0.0:2.4 with black 0.034 override

We see that we still lower gently the lower end of greyscale but not as much as above (and the same applies even if we would have given 99% output offset in the previous example). And this also applies to the Rec. 1886 curve and it's effect can be greater depending on the black level.

C. Hands on tone curve / gamma: creating 3DLUT for night usage

1. Since I know about this information, I want to have a 2.4 gamma like curve at the end, then I'll check the result with my favorite scenes with lot of contrast then I'll generate an another 3DLUT with a new tone curve settings.
2. I'll make a usual measurement but modifying the tone curve settings on the 3DLUT tab:
- gamma 2.4 , relative , 100% output offset (that would mean the "-Ib:1.0:2.4" switch for collink)
3. when it's done I test it with my favorite scenes looking for defects. In this case all looks good except for the little dark shadow details at the lower end of greyscale.
4. run HCFR, don't forget to apply your meter correction, and don't forget to set the applied tone curve in References tab by setting: ITU-R BT 1886 , 2.4 Effective, 0%
5. run a full measurement (54 patches)
6. go to the gamma graph and see how your curve looks like. In my case I want to lower the lower end.
7. open up References again and try out different values in it: I set 2%, hit apply, then take a look at the graph in the background. I don't like it, so I set 5%. If it looks pleasing then we done her so far. (Save the project for any future use ).
8. So I want to generate a new 3DLUT in dispalGUI:
- uncheck "Create #DLUT after profiling"
- and set the 5% value from HCFR: I have to enter 95% in dispalGUI
9. when it's done I test it with my favorite scenes looking for defects.
- if it's still not good then go back to step 6. in HCFR and try out different values

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post #4156 of 4593 Old 12-28-2015, 02:43 PM
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Ok, I think you mean this "Black level" setting on the calibration tab: http://dispcalgui.hoech.net/#settings_calibration_black_level
which is this http://www.argyllcms.com/doc/dispcal.html#B
The "problem" with this, since it's the first step during the whole process, you have to do the full calibration process again.

Can't this "-B" option of colprof be used to achieve the same result? If it can then it will be really useful for us to have this on the 3DLut page since we won't have to make new measurements.
Thanks. That looks like the setting. I'll have to try that for my next calibration. Not a big deal that I have to start over. I do that anyway every time Florian or Graeme release something new
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post #4157 of 4593 Old 12-28-2015, 08:09 PM
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Im having trouble getting my TVs image quality to where I want it. Everything seems too grainy, blacks seem washed out and are not dark enough and for some reason my 3DLUT makes things look worse. Before I profiled my Samsung UN50JU6500, I calibrated it with Chromapure and my i1 Pro (ES-1000). I adjusted the brightness and contrast based on the AVS CD, used the lowest brightness setting I could as long as 17 still blinked. After calibration I used Dispcal and very slightly adjusted the color high end for it to be happy around .3 dE at 120 luminance. I ran a 3500 patch with gamma 2.2 tone curve, black level drift compensation and the -H command which the ArgyllCMS documentation state improves the reading for the i1 Pro. All other settings were set based on the most up to date instructions from a few pages back. The verified profile looks great as far as I can tell.

Does anyone have any recommendations on fixing some of these image quality issues? Mainly I would like to reduce the grain, darken my blacks and optimize a 3DLUT to the fullest.

Here is the verification results after I ran the profile & 3DLUT
https://drive.google.com/file/d/0B5A...ew?usp=sharing

I have attached some comparison pictures and the profile results. The left half of the screen is without any 3DLUT active. Notice the face on the right half is more yellow/greenish with the 3DLUT active.

MadVR Settings
Chroma Upscaling: NNEDI3 32Neurons
Downscaling: Bicubic 50 sharp anti-ringing
Doubling: Double Luma NNEDI3, 16
Upscaling Lanczos 3 taps anti-ringing
Dithering: Error Diffusion option 1
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post #4158 of 4593 Old 12-28-2015, 09:04 PM
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Originally Posted by enphenate View Post
Im having trouble getting my TVs image quality to where I want it. Everything seems too grainy, blacks seem washed out and are not dark enough and for some reason my 3DLUT makes things look worse. Before I profiled my Samsung UN50JU6500, I calibrated it with Chromapure and my i1 Pro (ES-1000).
If you're using the i1pro spectro for measurements rather than just profiling a colorimeter, then that's likely to be your problem. Its not sensitive enough at lower levels and will either give you bad readings or no readings.
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post #4159 of 4593 Old 12-29-2015, 09:52 PM
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Is there a way to connect dispcalGUI to a madTPG instance on another machine on the local network? The release notes make it sound like this is possible but I cannot find any info how to do it.

Quote:
MadVR
Causes test patches to be displayed using the madVR Test Pattern Generator (madTPG) application which comes with the madVR video renderer (only available for Windows, but you can connect via local network from Linux and Mac OS X).
My HTPC is too far from my display to connect my colorimeter. I would like to run dispcalGUI using madVR from my laptop and connect to madTPG running on my HTPC. Any insight it greatly appreciated.
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post #4160 of 4593 Old 12-30-2015, 06:42 AM
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i know you can do this, but I never tried it my self.

try madHcCtrl.exe and make sure network is enabled.
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post #4161 of 4593 Old 12-30-2015, 02:32 PM
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Yeah I tried that. I believe everything is accessible from a networking perspective. I'm just not sure how to get dispcal to communicate with a remote instance of madTPG


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post #4162 of 4593 Old 12-31-2015, 02:53 AM
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I do that anyway every time Florian or Graeme release something new
That's madness!
Since we are here I profiled for day usage with max auto-generated patch set (~11100) with id3: the whole process ended in 4 hours (without verification). The result is slightly better than it is with ~2700 patches (according to xxxl verification).

Something else: I have created 3 correction matrix at the same time and all of them are different. Is it normal? Or is it just my panel of TV can produce this (8bit+FRC)? (And a continuous measurement both with i1pro and id3 keeps fluctuating, slightly changing values.)

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post #4163 of 4593 Old 12-31-2015, 02:56 AM
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Yeah I tried that. I believe everything is accessible from a networking perspective. I'm just not sure how to get dispcal to communicate with a remote instance of madTPG
Argyll CMS currently doesn't support madTPG over the network, but I've implemented the madVR network protocol for cross-platform support from other platforms (e.g. Mac OS X) in dispcalGUI. There's a way to enable this implementation for Windows, too:

  1. Close dispcalGUI.
  2. Edit C:\Users\YourUsername\AppData\Roaming\dispcalGUI\d ispcalGUI.ini in a text editor (e.g. Notepad, not Word!) and add a new line at the bottom:
    Code:
    madtpg.native = 0
  3. Save and close the file.
  4. On the PC that should run madTPG, open it and enable network access.
  5. Now launch dispcalGUI on the other PC and start calibration/profiling.
  6. In case it can't connect to madTPG, relaunch only madTPG (that should cause madTPG to connect to dispcalGUI automatically).

DisplayCAL - Graphical front-end for Argyll CMS display calibration and characterization
Current stable version 3.3.2 released 2017-06-29
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post #4164 of 4593 Old 12-31-2015, 03:24 AM
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Originally Posted by chros73 View Post
Something else: I have created 3 correction matrix at the same time and all of them are different. Is it normal? Or is it just my panel of TV can produce this (8bit+FRC)? (And a continuous measurement both with i1pro and id3 keeps fluctuating, slightly changing values.)
The differences usually aren't big, and below the perceptibility threshold. Slight fluctuations are also normal.

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post #4165 of 4593 Old 12-31-2015, 06:22 AM
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Argyll CMS currently doesn't support madTPG over the network
I might be missing something, but I've used madTPG over my local network before with just ArgyllCMS. In my experience (though it's been a while) it worked just fine so long as no other (e.g. local) madVR windows took precedence.
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post #4166 of 4593 Old 12-31-2015, 08:04 AM
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I might be missing something, but I've used madTPG over my local network before with just ArgyllCMS. In my experience (though it's been a while) it worked just fine so long as no other (e.g. local) madVR windows took precedence.
That would surprise me, because dispwin/dispcal/dispread use the madVR_BlindConnect API with searchLAN parameter set to 0 (false). You sure that worked? Because it didn't for me at the time I tested it, and I wouldn't have expected it to (that was months ago though).

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post #4167 of 4593 Old 12-31-2015, 08:13 AM
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Argyll CMS currently doesn't support madTPG over the network, but I've implemented the madVR network protocol for cross-platform support from other platforms (e.g. Mac OS X) in dispcalGUI.
My laptop is actually a Macbook, and I still cannot get discalGUI to connect to madTPG on my Windows 10 HTPC. I also tried your suggestion in my Windows 10 VM on my Macbook as well, but in both cases I just get an error that says "madTPG was not found or could not be launched." Any suggestions?
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post #4168 of 4593 Old 12-31-2015, 08:14 AM
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That would surprise me, because dispwin/dispcal/dispread use the madVR_BlindConnect API with searchLAN parameter set to 0 (false). You sure that worked? Because it didn't for me at the time I tested it, and I wouldn't have expected it to (that was months ago though).
I'm sure, although it really is a while ago so the APIs might have changed (this was before there was a 64-bit version of madVR). I did have to "Enable LAN Access" in the madVR tray icon and let it through my firewall (and I made sure to have madHcCtrl.exe running on both PCs by changing the tray icon settings to "always show tray icon").
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post #4169 of 4593 Old 12-31-2015, 08:19 AM
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I'm sure, although it really is a while ago so the APIs might have changed (this was before there was a 64-bit version of madVR). I did have to "Enable LAN Access" in the madVR tray icon and let it through my firewall (and I made sure to have madHcCtrl.exe running on both PCs by changing the tray icon settings to "always show tray icon").
Ok, that seems to make sense. The two madHcCtrl instances saw each other over the network, established the connection, and then dispcal/dispread simply connected to the local madHcCtrl instance.I guess the key was to have madHcCtrl running on both PCs prior to using dispcal/dispread.

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post #4170 of 4593 Old 12-31-2015, 08:39 AM
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Quote:
Originally Posted by johnsanc View Post
My laptop is actually a Macbook, and I still cannot get discalGUI to connect to madTPG on my Windows 10 HTPC. I also tried your suggestion in my Windows 10 VM on my Macbook as well, but in both cases I just get an error that says "madTPG was not found or could not be launched." Any suggestions?
You may have to poke some holes in your firewall. Note that if you're on a Mac, you don't need to make the config edit I mentioned.

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