Linearity testing.... - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 
Thread Tools
post #1 of 24 Old 05-22-2020, 07:52 PM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Linearity testing....

Hi, guys. I'm trying to prove which applications on the Mac are properly displaying color. I already calibrated my Dell UP2716D with my i1 Display pro. Using the Dell application (which is based on XRite) that writes the calibration into a 3D LUT in the monitor.

So now, with the calibrated monitor, I should be able to read its luminance and chrominance (R, G, and B) levels in Calman, using swatches I generated in Photoshop with color management turned off in Photoshop. I did a spreadsheet to calculate what % of 255 in order to create each 10% swatch. For example, 100% white is 255,255,255. 10% white should be 25,25,25.

I also turned those swatches into .mp4 movies using Adobe Media Encoder so I could play them as movies in Quicktime and other applications, to prove that each app was respecting the colorsync profile.

I'm effectively running Calman on a separate computer, but it might blow your mind that I have it in Parallels running in windows on the Mac. But it senses the i1 Display pro fine.

Here's where it gets crazy. First of all, Calman is set up for Blu-Ray video with 16-235 levels. But I want to proof full levels since I'm testing a workflow for eventual playback in YouTube.

But still, calman should be able to read the incoming luminance levels regardless of how they are encoded on the source side. I chose the luminance check "workflow" and "read continuous". The only reading that makes any sense is my 100% swatch reads 127 nits, close enough to show I'm in the ballpark. But the 50% swatch is reading way low and they all are off from there. Color indications in Calman are also way off except for a couple of the source swatches. And I'm just not sure if the luminance workflow is the best one because it asks to see whichever swatch is being generated and maybe it has to expect some level instead of just reading it.

Can anyone recommend an application (or a workflow in Calman) where I can just do a continuous reading and also read R,G, and B levels?
bobkatz is offline  
Sponsored Links
Advertisement
 
post #2 of 24 Old 05-23-2020, 12:38 AM
AVS Forum Special Member
 
Light Illusion's Avatar
 
Join Date: Aug 2010
Posts: 2,182
Mentioned: 38 Post(s)
Tagged: 0 Thread(s)
Quoted: 1004 Post(s)
Liked: 1597
The Dell calibration application will not have loaded a 3D LUT into the monitor.
At best, it will have loaded a 1D LUT and 3x3 matrix, and may have additional volumetric information in an associated ICC profile.
(It's not even definite a 1D LUT is used in the monitor, but may be a VCGT in the graphics card, with no 3x3 matrix...)
The specs on the monitor I can find are not at all clear on this.

For issues with such calibration software please see: https://www.lightspace.lightillusion..._profiles.html

Steve

Steve Shaw
LIGHT ILLUSION

Light Illusion is online now  
post #3 of 24 Old 05-23-2020, 02:36 AM
Member
 
Join Date: Mar 2016
Location: India
Posts: 79
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked: 31
Quote:
Originally Posted by bobkatz View Post
Can anyone recommend an application (or a workflow in Calman) where I can just do a continuous reading and also read R,G, and B levels?
I suppose you would want to read XYZ/xyY values instead of RGB levels? Or are you talking about the input RGB values (which I guess should already be known to you)?

When a probe takes a color measurement, it returns XYZ values for the measured color. You will get chromaticity (x,y) and luminance (Y) information for the test patch when XYZ is converted to xyY. Well, XYZ values can also be converted to RGB with respect to a color space, if that color space contains the measured color. You can use HCFR if you really need to see RGB values, and it will also show XYZ/xyY.

Note that when you upload a video in Youtube, the colors of the uploaded video as seen in Youtube will not match with the colors seen when you play the file locally. It's because Youtube does some color processing on the uploaded videos.

Last edited by omarank; 05-23-2020 at 02:41 AM.
omarank is online now  
Sponsored Links
Advertisement
 
post #4 of 24 Old 05-25-2020, 01:56 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Thanks, guys. I'm very pleased and thankful that several experts, including Light Illusion have replied to my plea. And that the gentleman from Light Illusion corrected my misunderstanding about my Dell Monitor and its under-the-hood color correction technology. In fact, I just learned by studying your page that my wife's Eizo CG2730 also does not have a 3d LUT! Quite surprising given the high cost of that monitor.

I just "assumed" that it did have a 3D LUT. Regardless, I've found the Delta E results on her monitor using ColorNavigator, and on my Dell using its application seem to be pretty good. At least the Dell and the Eizo limit the gamuts to the color space that has been chosen.

Back to my question, I'm looking for a simple substitute for Calman so I can see what's going on when I play swatches in Adobe Premiere Pro. I'll check out HFCR as posted by another expert in this thread. Please stand by.


Best regards,


Bob Katz

Quote:
Originally Posted by Light Illusion View Post
The Dell calibration application will not have loaded a 3D LUT into the monitor.
At best, it will have loaded a 1D LUT and 3x3 matrix, and may have additional volumetric information in an associated ICC profile.
(It's not even definite a 1D LUT is used in the monitor, but may be a VCGT in the graphics card, with no 3x3 matrix...)
The specs on the monitor I can find are not at all clear on this.

For issues with such calibration software please see: https://www.lightspace.lightillusion..._profiles.html

Steve
bobkatz is offline  
post #5 of 24 Old 05-25-2020, 02:15 AM
AVS Forum Special Member
 
Light Illusion's Avatar
 
Join Date: Aug 2010
Posts: 2,182
Mentioned: 38 Post(s)
Tagged: 0 Thread(s)
Quoted: 1004 Post(s)
Liked: 1597
The Free version of LightSpace can be used as you require, and so will the free version of ColourSpace, when available.
https://www.lightillusion.com/free.html

Steve

Steve Shaw
LIGHT ILLUSION

Light Illusion is online now  
post #6 of 24 Old 05-25-2020, 06:31 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Thanks all for the introduction to HCFR. It's dedicated to a different purpose than Calman and allowed me to measure and compare Quicktime Pro vs. Premiere Pro with and without color management. Proved that at the critical 10 to 20% white PP performs better with DISPLAY COLOR MANAGEMENT TURNED OFF.

The fault is apparently with PP because Quicktime Pro does much better from 0-10% white. I wonder if I could make a better Colorsync profile

The Dell UP2716D monitor uses a modified version of XRite Profiler made by XRite for their Dell application. Of course it knows at the top that the Dell uses a GN-BLU LED, which is an inconsequential thing. The main difference is that at the end of the calibration process, the application saves something into the calibration memory of the Dell. Whether it's a LUT or a matrix or whatever remains a mystery. Dell's not telling. :-(

I wonder if I can produce a better ICC profile for the Dell using HCFR. One of them dedicated to Premiere, one to Quicktime. Which I can do because HCFR allows external swatches and I can play Premiere or Quicktime like a disk player.

Does anyone have a script for changing profiles from the command line or Applescript? Thanks a lot for your help.
bobkatz is offline  
post #7 of 24 Old 05-25-2020, 06:34 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Quote:
Originally Posted by Light Illusion View Post
The Free version of LightSpace can be used as you require, and so will the free version of ColourSpace, when available.
https://www.lightillusion.com/free.html

Steve
Thanks, Steve. I'm overloaded with calibration apps on Mac and PC. Sometimes I can't remember which one I'm supposed to use. I have to keep careful notes :-)
bobkatz is offline  
post #8 of 24 Old 05-25-2020, 07:28 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
By the way, I sent the author of HCFR a little donation as it's a very nice little test application.

Now that I know that neither Quicktime nor Premiere is perfect and my Dell monitor leaves something to be desired, I'd like to move forward with the goal of seeing if I can make Quicktime on the Mac and Premiere Pro on the mac perform more correctly and more similarly. I've seen a large difference in color between the two applications. HCFR reveals that Quicktime Pro is the more accurate of the two, in the critical 10-20% gray range.

I"m dependent on the Dell application to save some sort of calibration data into the memory of the Dell and also it generates an ICC profile that includes some further correction. Maybe, if I'm lucky, I can create a custom profile for each application I use on the Mac. My hope is that by using Premiere or Quicktime as the pattern generator I can make a custom profile for Quicktime and another for Premiere. Maybe it won't prove any better, but you never know. I want to try.

Previously I've used Calman to create a 3D LUT for use in JRiver with MADVR. I see that Calman can also create an ICC profile. But it looks like Calman needs to use its own pattern generator (a remote-controlled pattern generator on a client computer). Does anyone know if Calman is capable of using an independent pattern generator, like a "simulated Blu-ray player" to generate the patches that it needs?

It gets deep, of course. I imagine I should play from Premiere using a LINEAR profile to do the analysis and then with luck the new ICC profile that is generated will compensate for all of Premiere's mistakes. Or maybe not, maybe Premiere is just not capable of reading an ICC profile very well. But it's worth a try.

I know, all this to avoid spending a fortune on a video monitor with a 3D LUT! Maybe someday. If only there were something like MADVR available for Mac that would use a software 3D LUT to do display correction for all sources on the mac.
bobkatz is offline  
post #9 of 24 Old 05-25-2020, 08:17 AM
AVS Forum Special Member
 
Light Illusion's Avatar
 
Join Date: Aug 2010
Posts: 2,182
Mentioned: 38 Post(s)
Tagged: 0 Thread(s)
Quoted: 1004 Post(s)
Liked: 1597
Quote:
Originally Posted by bobkatz View Post
I see that Calman can also create an ICC profile. But it looks like Calman needs to use its own pattern generator (a remote-controlled pattern generator on a client computer). Does anyone know if Calman is capable of using an independent pattern generator, like a "simulated Blu-ray player" to generate the patches that it needs?
No, but LightSpace/ColourSpace can, using DIP mode.
See: https://www.lightspace.lightillusion...time_per_frame
And SpaceMan can be used for ICC generation.

Steve

Steve Shaw
LIGHT ILLUSION

Light Illusion is online now  
post #10 of 24 Old 05-25-2020, 09:27 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
To summarize: Since Calman must use its own pattern generator, I'm now looking for an application that can create an ICC profile and use an independent generator, manually-controlled, like Premiere or Quicktime Player, to play patches --- and then generate an ICC profile.

Light Illusion replied that Colorspace can do this in DIP mode. I'm sorry that Colorspace/Lightspace is out of my budget. Is there any less expensive application that would allow me to do this?
bobkatz is offline  
post #11 of 24 Old 05-25-2020, 09:37 AM
Member
 
Join Date: Mar 2016
Location: India
Posts: 79
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked: 31
Quote:
Originally Posted by bobkatz View Post
I wonder if I can produce a better ICC profile for the Dell using HCFR. One of them dedicated to Premiere, one to Quicktime. Which I can do because HCFR allows external swatches and I can play Premiere or Quicktime like a disk player.

Does anyone have a script for changing profiles from the command line or Applescript? Thanks a lot for your help.
You can use Argyll's dispwin command to install/change an ICC profile for your monitor. A script can also be created.

If you want to color match Premiere Pro and Quicktime, there is another thing that can be tried. Your Monitor ICC profile can be converted to a LUT, and that LUT can be loaded in Premiere Pro via Lumetri Color panel. ICC color management should then be disabled in Premiere Pro. You can then see if the colors match between the two applications. To give an explanation to this approach, the idea is, if your Monitor ICC profile is a basic one (with just VCGT data or RGB channel curves, primaries coordinates and chromatic adaptation matrix), Quicktime would be applying a simple color transform to process the video. That transform can be generated externally and saved as a LUT to be used in Premiere Pro. So, in all likelihood, colors between the two applications should match then. However, if your Monitor ICC profile supports different gamut mapping modes with A2B/B2A tables for different intents etc, then different kinds of color transforms may be generated by different applications and more complex methods would be required to probe the transform that Quicktime is generating on the fly.

For highest color accuracy, you should profile your monitor with a large sequence of color test patches and get a Calibration 3DLUT, which when loaded in Premiere Pro will do a volumetric color correction for your monitor, and this way Premiere Pro output would be your reference output.


Quote:
Originally Posted by bobkatz View Post
Does anyone know if Calman is capable of using an independent pattern generator, like a "simulated Blu-ray player" to generate the patches that it needs?
I don't think it's possible with CalMAN. You can use DisplayCAL's untethered mode or DIP mode in LightSpace/ColourSpace.


Quote:
Originally Posted by bobkatz View Post
It gets deep, of course. I imagine I should play from Premiere using a LINEAR profile to do the analysis and then with luck the new ICC profile that is generated will compensate for all of Premiere's mistakes. Or maybe not, maybe Premiere is just not capable of reading an ICC profile very well. But it's worth a try.
I am not sure if there is anything like a Linear ICC Device Profile. A Display ICC Device Profile will be for some color space.

If you used Resolve instead of Premiere Pro, you could use DisplayCAL to display patterns via Resolve's internal test pattern generator (just like you used madTPG for madVR calibration 3DLUT). CalMAN and LightSpace can also be used (but will require you to buy a license).
omarank is online now  
post #12 of 24 Old 05-25-2020, 09:39 AM
Member
 
Join Date: Mar 2016
Location: India
Posts: 79
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked: 31
Quote:
Originally Posted by bobkatz View Post
Light Illusion replied that Colorspace can do this in DIP mode. I'm sorry that Colorspace/Lightspace is out of my budget. Is there any less expensive application that would allow me to do this?
As mentioned above, you can try DisplayCAL's untethered mode. DisplayCAL is free software.
omarank is online now  
post #13 of 24 Old 05-25-2020, 09:40 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Please forgive the multiple posts!

I have another thought: HCFR has revealed that the red levels in the Dell are meaningfully lower than the G and B levels after its calibration.

I'm wondering if I can do this:

1) Instead of using Cal 1 and Cal 2 in the Dell, I set it to custom color and adjust its white point and black point levels manually using HCFR and HCFR's pattern generator and a linear Profile in OSX Displays. I can also do color temperature and a few other tweaks in custom color. The old fashioned way we used to do with CRTs. This gets the monitor to the closest it can get come with its internal adjustments. Pity I can't save that to a Cal slot, but custom color will have to do.

2) Since I do both still photography and video: I switch to i1Profiler and I create a profile for 120 Nits with something close to BT.1886 gamma, for use with video. I then create another profile set to 80 Nits for use with Adobe RGB and Adobe RGB Gamma (2.2).

3) I test Premiere Pro running swatches in HCFR and use it with color management off or on, whichever is most accurate according to HCFR.

4) Quicktime Player will hopefully be even more friendly than Premiere with this new profile for the Dell.

And some day, I get a new monitor with an integral 3D LUT!
bobkatz is offline  
post #14 of 24 Old 05-25-2020, 01:25 PM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Quote:
Originally Posted by omarank View Post
You can use Argyll's dispwin command to install/change an ICC profile for your monitor. A script can also be created.

If you want to color match Premiere Pro and Quicktime, there is another thing that can be tried. Your Monitor ICC profile can be converted to a LUT, and that LUT can be loaded in Premiere Pro via Lumetri Color panel. ICC color management should then be disabled in Premiere Pro. You can then see if the colors match between the two applications. To give an explanation to this approach, the idea is, if your Monitor ICC profile is a basic one (with just VCGT data or RGB channel curves, primaries coordinates and chromatic adaptation matrix), Quicktime would be applying a simple color transform to process the video. That transform can be generated externally and saved as a LUT to be used in Premiere Pro. So, in all likelihood, colors between the two applications should match then. However, if your Monitor ICC profile supports different gamut mapping modes with A2B/B2A tables for different intents etc, then different kinds of color transforms may be generated by different applications and more complex methods would be required to probe the transform that Quicktime is generating on the fly.

For highest color accuracy, you should profile your monitor with a large sequence of color test patches and get a Calibration 3DLUT, which when loaded in Premiere Pro will do a volumetric color correction for your monitor, and this way Premiere Pro output would be your reference output.



I don't think it's possible with CalMAN. You can use DisplayCAL's untethered mode or DIP mode in LightSpace/ColourSpace.



I am not sure if there is anything like a Linear ICC Device Profile. A Display ICC Device Profile will be for some color space.

If you used Resolve instead of Premiere Pro, you could use DisplayCAL to display patterns via Resolve's internal test pattern generator (just like you used madTPG for madVR calibration 3DLUT). CalMAN and LightSpace can also be used (but will require you to buy a license).
Thanks for the information, Omarank

I already know about using a 3D LUT in Lumetri Premiere to compensate for Display and act like a display profile. But the workflow gives me the creeps... to remember to remove the LUT before exporting and then put it in when editing seems like a recipe for disaster and mindf*cks. Unless you know some other trick...

I tried Display Cal previously and rejected it for my purposes because I didn't think it had something like its "untethered" mode.

Nevertheless, reading about untethered mode at the link you gave me gives me the chills.

I'm going to try yet another, different workflow! First I'll adjust the Dell monitor as closely as possible HCFR using custom color, setting luminance, black and white points and color temperature in the monitor with a linear profile. Or at least what I think is a linear profile. It's the profile left around by i1Display called "DisplayProfile_Linear.icc" which i1 uses during its calibration process.

In fact, I'm surprised that Display Cal doesn't switch to a linear profile during its measurement. It only switches to a linear profile if it sees that we're re-profiling with a profile it had already created. Strange. There seems to be a mode where it will go to a linear profile, but I get rather mixed up by all the deep controls in Display Cal. It's a DEEP program and looks like it will produce a very good Delta E as well.

I'll come back here after I do a little more experimenting and learning! STand by for the fireworks!
bobkatz is offline  
post #15 of 24 Old 05-26-2020, 10:29 AM
Member
 
Join Date: Mar 2016
Location: India
Posts: 79
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked: 31
Quote:
Originally Posted by bobkatz View Post
I'm going to try yet another, different workflow! First I'll adjust the Dell monitor as closely as possible HCFR using custom color, setting luminance, black and white points and color temperature in the monitor with a linear profile. Or at least what I think is a linear profile. It's the profile left around by i1Display called "DisplayProfile_Linear.icc" which i1 uses during its calibration process.
The linear profile you are referring to is an ICC Device Profile with a Linear VCGT, which when installed as a Monitor ICC profile will load a Unity 1DLUT in the GPU gamma table (VCGT). The other gamut information that it carries will make an ICC aware application generate a color transform that distorts the colors. So, when this profile is installed, you will see distorted colors and you will know the profile is active. And when you disable the ICC color management in an ICC aware application, the image frames outputted by the application are sent to the GPU frame buffer without any color manipulation/correction - as the VCGT is also set to Unity. To summarize, that X-Rite linear profile serves to ensure that no color management is active with respect to an ICC aware application, if you have disabled the ICC color management in that application.

In case you have been thinking that the X-Rite profile is some kind of a passthrough profile in itself, it is not. It can be used though to get a passthrough/no color management state with respect to an application.
omarank is online now  
post #16 of 24 Old 06-02-2020, 08:11 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Wow! You guys know so much. I spend my life as a professional audio engineer but in the video color field, I am just a learner.

Thanks all, for the advice. I finally got round to analyzing the output of Premiere Pro versus Quicktime, using HCFR and i1 Display Pro. And compared it with the internal generator of HCFR going through Apple's Color Profile + the Dell Cal 2 position for rec.709. Each application reveals its strengths and weaknesses, neither one is as accurate as the HCFR generator itself. To complicate matters, I run HCFR in Parallels/Win 10 so I'm not 100% sure if Parallels recognizes Apple's colorsync for application output.

HCFR on OSX does not support the i1 Pro colorimeter. Maybe someday I can master "untethered" mode in Display Cal so I don't have to use Parallels. All I want is to make a 10 step grayscale test chart that can be used in untethered mode in Display Cal for this purpose, as I'm not profiling, I'm just doing basic research at this point. And untethered mode with a giant test chart would be masochistic.

Bottom line: Looks like I'm going to have to eventually create a 3D LUT for "monitor correction" in Premiere because of my OCD. :-)


Best wishes,


Bob


Quote:
Originally Posted by omarank View Post
The linear profile you are referring to is an ICC Device Profile with a Linear VCGT, which when installed as a Monitor ICC profile will load a Unity 1DLUT in the GPU gamma table (VCGT). The other gamut information that it carries will make an ICC aware application generate a color transform that distorts the colors. So, when this profile is installed, you will see distorted colors and you will know the profile is active. And when you disable the ICC color management in an ICC aware application, the image frames outputted by the application are sent to the GPU frame buffer without any color manipulation/correction - as the VCGT is also set to Unity. To summarize, that X-Rite linear profile serves to ensure that no color management is active with respect to an ICC aware application, if you have disabled the ICC color management in that application.

In case you have been thinking that the X-Rite profile is some kind of a passthrough profile in itself, it is not. It can be used though to get a passthrough/no color management state with respect to an application.
bobkatz is offline  
post #17 of 24 Old 06-02-2020, 08:27 AM
Advanced Member
 
peniku8's Avatar
 
Join Date: Dec 2018
Location: Germany
Posts: 794
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 431 Post(s)
Liked: 430
Quote:
Originally Posted by bobkatz View Post
I'm overloaded with calibration apps on Mac and PC. Sometimes I can't remember which one I'm supposed to use. I have to keep careful notes :-)
That about sums it up really well. I guess that's why my dad has gotten an EIZO with an integrated calibrator. I'm not exactly sure if that's comparable, accuracy wise, but it's convenient for sure.

A Star Is Born - Lady Gaga goes Rock Audio&Video by Ocean Studios (me)
SKHorn Build
Samsung KS7500 - Marantz NR1504 - Klipsch R-26F - Klipsch R-25C - Klipsch R-15M - SKHorn - BOSS
Bass EQ for Filtered Video Games
peniku8 is offline  
post #18 of 24 Old 06-02-2020, 09:44 AM
Member
 
Join Date: Mar 2016
Location: India
Posts: 79
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked: 31
Quote:
Originally Posted by bobkatz View Post
Wow! You guys know so much. I spend my life as a professional audio engineer but in the video color field, I am just a learner.

Thanks all, for the advice. I finally got round to analyzing the output of Premiere Pro versus Quicktime, using HCFR and i1 Display Pro. And compared it with the internal generator of HCFR going through Apple's Color Profile + the Dell Cal 2 position for rec.709. Each application reveals its strengths and weaknesses, neither one is as accurate as the HCFR generator itself. To complicate matters, I run HCFR in Parallels/Win 10 so I'm not 100% sure if Parallels recognizes Apple's colorsync for application output.

HCFR on OSX does not support the i1 Pro colorimeter. Maybe someday I can master "untethered" mode in Display Cal so I don't have to use Parallels. All I want is to make a 10 step grayscale test chart that can be used in untethered mode in Display Cal for this purpose, as I'm not profiling, I'm just doing basic research at this point. And untethered mode with a giant test chart would be masochistic.
You are an eminent figure in audio. I guess you don't need to introduce yourself.

Untethered mode can be used in two ways:

1. For Manual Measurements where you step through a pre-defined list of patches and take measurements manually.

A 10 step greyscale chart is small enough that you can take the measurements manually. So, you can use the Untethered mode in this way. All you need to do is just uncheck 'Auto' after you click on 'Profile only' in the Display tab in DisplayCAL, so as to enable the Manual mode.


2. For Automatic Measurements of a patch set. Here 'Auto' needs to be checked.

This method sounds complicated from the description, but it is not that difficult if you try it. If you have any questions about it, maybe I can help.
omarank is online now  
post #19 of 24 Old 06-03-2020, 02:33 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Dear Omarank: Thanks for your kind words and your advice. I'll try that 10 step approach with Display cal in manual right away! It should avoid any questions about using HCFR in Parallels.

Very best wishes,


Bob


Quote:
Originally Posted by omarank View Post
You are an eminent figure in audio. I guess you don't need to introduce yourself.

Untethered mode can be used in two ways:

1. For Manual Measurements where you step through a pre-defined list of patches and take measurements manually.

A 10 step greyscale chart is small enough that you can take the measurements manually. So, you can use the Untethered mode in this way. All you need to do is just uncheck 'Auto' after you click on 'Profile only' in the Display tab in DisplayCAL, so as to enable the Manual mode.


2. For Automatic Measurements of a patch set. Here 'Auto' needs to be checked.

This method sounds complicated from the description, but it is not that difficult if you try it. If you have any questions about it, maybe I can help.
bobkatz is offline  
post #20 of 24 Old 06-03-2020, 07:01 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Dear Omarank and other DisplayCal experts:

Thanks for your help, it's much appreciated.

My goal is to test and compare an 11 step (10% increment 0 through 100) grayscale using a Dell UP2716D monitor hopefully corrected to rec.709/BT.1886. Three different ways: 1) directly in Display Cal 2) playing these in Adobe Premiere. 3) Playing these in Quicktime

I have these patches I created in Photoshop and also turned into movies so I can already play them in Quicktime or Premiere. Now, thanks to Omarank's guidance I know how to play the same 11-step grayscale in DisplayCal.

Omarank referred to using DisplayCal in "profile" mode untethered. I can do that, no problem, but I don't understand where to go next, because DisplayCal generates a profile at that point and now I'm confused. There's also a "Verification" tab in Displaycal that produces a report, but the settings in that tab also confuse me.

So that's where my knowledge stops.

Thanks in advance!!!!


Quote:
Originally Posted by bobkatz View Post
Dear Omarank: Thanks for your kind words and your advice. I'll try that 10 step approach with Display cal in manual right away! It should avoid any questions about using HCFR in Parallels.

Very best wishes,


Bob
bobkatz is offline  
post #21 of 24 Old 06-03-2020, 07:12 AM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Quote:
Originally Posted by bobkatz View Post
Dear Omarank and other DisplayCal experts:

Thanks for your help, it's much appreciated.

My goal is to test and compare an 11 step (10% increment 0 through 100) grayscale using a Dell UP2716D monitor hopefully corrected to rec.709/BT.1886. Three different ways: 1) directly in Display Cal 2) playing these in Adobe Premiere. 3) Playing these in Quicktime

I have these patches I created in Photoshop and also turned into movies so I can already play them in Quicktime or Premiere. Now, thanks to Omarank's guidance I know how to play the same 11-step grayscale in DisplayCal.

Omarank referred to using DisplayCal in "profile" mode untethered. I can do that, no problem, but I don't understand where to go next, because DisplayCal generates a profile at that point and now I'm confused. There's also a "Verification" tab in Displaycal that produces a report, but the settings in that tab also confuse me.

So that's where my knowledge stops.

Thanks in advance!!!!
Dear Omarank:

OK, maybe I have the "verification" tab figured out, by playing with settings. And it can work untethered. I'll test it out later. Please stand by!
bobkatz is offline  
post #22 of 24 Old 06-03-2020, 08:35 AM
Member
 
Join Date: Mar 2016
Location: India
Posts: 79
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked: 31
Quote:
Originally Posted by bobkatz View Post
Omarank referred to using DisplayCal in "profile" mode untethered. I can do that, no problem, but I don't understand where to go next, because DisplayCal generates a profile at that point and now I'm confused. There's also a "Verification" tab in Displaycal that produces a report, but the settings in that tab also confuse me.
Once you have taken the measurements, DisplayCAL records the measurement data in a .ti3 file and it also creates an ICC profile for the display. If you need to evaluate the raw data, just open the .ti3 file in any text editor and access the data. If you want to see a report on how the measurements align with respect to a color space, you can go for verification.

You will find the data file and the ICC profile in Appdata/Roaming/DisplayCAL/storage.

To do a verification, you need a patchset (a testchart in DisplayCAL). You can use the same patchset you used for profiling or select from the preset ones or you can create a new one. From the settings dropdown, select the ICC profile that DisplayCAL created. The color space against which you are evaluating will be your simulation profile. In your case, you will select Rec709 profile there. Select 'Use simulation profile as display profile'. If you are verifying for Rec709 Gamma 2.4, select Tone Curve as 'Apply black output offset (100%)'. If you are verifying for Rec709 BT.1886 EOTF, select Rec.1886/ Gamma 2.4/ Absolute from the three dropdowns.

Well, I personally don't use DisplayCAL's verification feature. I suggested the above settings out of a general understanding of the options. If anything doesn't work as intended, let me know.

Last edited by omarank; 06-03-2020 at 08:41 AM.
omarank is online now  
post #23 of 24 Old 06-03-2020, 05:25 PM - Thread Starter
Member
 
bobkatz's Avatar
 
Join Date: Jun 2006
Posts: 64
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 11
Dear Omarank:

Again, thanks.

I went through a verification. The only tricky part about your guess at how this page works is
that the option to perform the verification (button "Measurement report" is greyed out if I check "use simulation profile as display profile." So I unchecked that. I also was uncomfortable with choosing "rec.709 ITU-R BT.709" as the simulation profile but I tried that and I also tried the colorsync profile that's being used. Either way, the results were abysmal.

In the mid band, Delta E is very bad, off the charts, sometimes as much as 4. The curve of delta E error goes from green in the near-black range to red (very bad) in the mid range and again moves towards green in the white range. Something must be wrong in my verification method, the display can't be that bad! I think I got far better results with HFCR in Windows (Parallels). You'd think if Parallels does NOT respect the ICC profile, then the results would be very bad, so perhaps HFCR is working, at least based on the generally positive results.

Perhaps I should reach out to DisplayCal's designer and discuss the verification. There might be an initial measurement report I could learn to interpret that would tell me how well the profile is working. That might work for verification of the original creation of the profile, but I see no way of avoiding the "verification" for checking Premiere or Quicktime performance.

Maybe you have some ideas, if you are still game to help, which I do appreciate! If you ever need professional audio advice, I can lend an ear.


Best wishes,


Bob


Quote:
Originally Posted by omarank View Post
Once you have taken the measurements, DisplayCAL records the measurement data in a .ti3 file and it also creates an ICC profile for the display. If you need to evaluate the raw data, just open the .ti3 file in any text editor and access the data. If you want to see a report on how the measurements align with respect to a color space, you can go for verification.

You will find the data file and the ICC profile in Appdata/Roaming/DisplayCAL/storage.

To do a verification, you need a patchset (a testchart in DisplayCAL). You can use the same patchset you used for profiling or select from the preset ones or you can create a new one. From the settings dropdown, select the ICC profile that DisplayCAL created. The color space against which you are evaluating will be your simulation profile. In your case, you will select Rec709 profile there. Select 'Use simulation profile as display profile'. If you are verifying for Rec709 Gamma 2.4, select Tone Curve as 'Apply black output offset (100%)'. If you are verifying for Rec709 BT.1886 EOTF, select Rec.1886/ Gamma 2.4/ Absolute from the three dropdowns.

Well, I personally don't use DisplayCAL's verification feature. I suggested the above settings out of a general understanding of the options. If anything doesn't work as intended, let me know.
bobkatz is offline  
post #24 of 24 Old 06-04-2020, 05:54 AM
Member
 
Join Date: Mar 2016
Location: India
Posts: 79
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked: 31
Quote:
Originally Posted by bobkatz View Post
I went through a verification. The only tricky part about your guess at how this page works is
that the option to perform the verification (button "Measurement report" is greyed out if I check "use simulation profile as display profile." So I unchecked that.
Ok. Actually, if we take reference of a comment of Florian (DisplayCAL's author) on this setting:
"This setting is only useful in a scenario where a display is adjusted to match the selected simulation target without ICC color management, i.e. by using the display controls, an external 3D LUT box or similar."

there is an implication that "Use simulation profile as display profile" is useful for an untethered display which has been calibrated. Even if your display is calibrated via ICC profile, you profiled it in Untethered mode, so DisplayCAL does not really know what display it is and whether it is even connected to the system on which DisplayCAL is running. That's why I suggested it. Perhaps DisplayCAL handles the untethered mode profiling differently, or maybe my understanding of this setting is incorrect.

Can you just share the DisplayCAL data with me? You will find it in the storage folder in the location I described previously. As I see your data, I can probably help you out with the verification.

Please check my PM.


Quote:
Originally Posted by bobkatz View Post
I also was uncomfortable with choosing "rec.709 ITU-R BT.709" as the simulation profile but I tried that and I also tried the colorsync profile that's being used. Either way, the results were abysmal.
As you mentioned that your monitor is calibrated (perhaps not perfectly) to Rec709/BT.1886, you will have to select the target space accordingly. The current standard for Rec709 specifies Gamma 2.4 (although you can target any gamma as per your viewing environment). But if your calibration is for BT.1886, again the tone curve will have to be specified accordingly.

I am not sure why you were uncomfortable choosing Rec709 simulation profile. You need to specify a target color space so as to make the application aware for what target you want to do the verification.

As for the unexpected results, I suppose you did not specify the correct tone curve. In fact I should be blamed here. When I suggested that "If you are verifying for Rec709 Gamma 2.4, select Tone Curve as 'Apply black output offset (100%)'", it skipped my mind that the Rec709.icm profile in Argyll/DisplayCAL corresponds to Rec709 encoding gamma while the display would have been (and should have been) calibrated to power gamma 2.4. So, instead of selecting Tone Curve as 'Apply black output offset (100%)', you need to select Gamma 2.4/ Relative.

My suggestion for BT.1886 verification was correct though: "If you are verifying for Rec709 BT.1886 EOTF, select Rec.1886/ Gamma 2.4/ Absolute from the three dropdowns".

I believe if you the Tone curve correctly, your verification results would be correct.

Anyway, as I see your data, I should be able to help you further on this.


Quote:
Originally Posted by bobkatz View Post
If you ever need professional audio advice, I can lend an ear.
I am really obliged. Thank you!

I will surely connect with you sometime on convolution related things.
omarank is online now  
Sponsored Links
Advertisement
 
Reply Display Calibration

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off