Rocky & ICC Profiles

[allklier]

Had a good reminder of the importance of setting up the right ICC profiles in Rocky.

My Eizo GUI monitors are profiled, but didn’t match the FSI reference. They were a bit flatter and desaturated. Turns out when I installed Rocky 9.3 it assigned some automated ICC profile to both monitors, including a 6,400K white point???

Since I have calibrated .icc files from the windows system the monitors are shared with, it was simple to grab them, and then through the display settings in Gnome import those for both monitors. Now they match the FSI again.

It was very distracting to have monitors side-by-side that disagreed.

Even if you have a good and calibrated GUI monitor, don’t assume that Rocky knows what to do with that if you don’t double check.

I can post some screen grabs of the settings screens if helpful.

[theoman]

I for one would love some help on this. I have never calibrated my monitor or Rocky OS for flame. I know i know i should have, many many times! could you send a brief how to or some documentation? My Benq can do rec709. What should i be doing for best practices?

[allklier]

So the process depends a bit on your monitor. Not familiar with the BenQ.

Somehow you need to find a way to create an .icc profile that matches your specific monitor.

These days a lot of monitors have calibration probes built-in, but you need to use host software to run them, which will create the ICC profile. The likely issue is that this software is rarely available for Linux. But you can run it from a Mac or Windows laptop if you have one.

In my case the Eizo CG monitors have a built-in probe, but save an ICC profile that can be exported. If your monitor doesn’t have a probe, you can buy an Xrite or other monitor calibration probe.

Let’s assume you found a way to generate the .icc profile. Move them into a folder on Rocky, and then in the GUI, top right corner go to ‘Settings’ and then ‘Color’.

You’ll see your monitors listed.

If you click on one and expand, you can see the currently assigned profile:

Now, if you click on the monitor name again, at the bottom there’s a ‘Add Profile’ button. Click that and import the ICC profile you made.

Add and activate. You can delete or keep the previous one. Just make sure the one you added is the active one.

All done. If everything went well, your monitor should now match what you see on your broadcast display.

[theoman]

thank you! ill go through this when my probe comes today. besides the profile what color setting do you set your monitor to? i have options: Adobe RGB, sRGB, BW, rec 709, DCI-P3, displayP3, M book. i have it set to rec709 but will that limit my gamut when im viewing aces / log material etc

[allklier]

For video post, your monitor should be set to Rec709 (i.e. sRGB color primaries, Gamma 2.4, 100cdm brightness).

If you have log material, you should make use color management with a view transform to Rec709. It’s not realistic to match your monitor to various materials through monitor settings.

That is if you work in SDR. There are comparable settings for HDR work.

[theoman]

Yes great! Thanks for confirming

[finnjaeger]

How reliable are these ICC profiles in rocky?

Are they actually applied in flame? or is flame reading them to make them a target colorspace for their stuff? is it applied in a webbrowser too? usually its application dependant what uses these iccs and what doesnt which can lead to some highly confusing situations.

Help

not clear to me how this works behind the scenes in linux to be honest. in macOS you have a setting to enable the use of ICC profiles but not in linux.

ICC is in my experience more than dangerous, if your monitors are both hardware calibratable , you should remove any ICC stuff and have the monitor handle this, same for macOS or linux, you just tell linux to not touch the image data, and on macOS you tell it your monitor is sRGB to invert colorsync bullcrap

right now it sounds like your monitors are running in some kind of native mode requiring these ICC profiles to correct he data flame/OS puts out to match the native gamut and state of the monitor.

of your monitor had these calibration profiles internally you wouldnt have to mess with it.

also flame as per the docs only uses the ICC profile of your main monitor so having 2 with different ICC profiles would cause utter havok.

Really not a fan of ICC things, its a messy , ugly, and unreliable thing

[allklier]

Good question.

Empirically I can say that switching to the correct ICC profile in Rocky, which was created by Eizo Color Navigator while running on Windows to the same monitor did have a noticeable and positive impact on color matching the Eizo monitor to the FSI. So yes, they did work in my specific use case in Linux.

The caveat is that the Eizos (and they’re carved out on the ADSK help page) have internal calibration, and it’s not 100% clear where these ICC profiles are applied - is the NVidia driver and GPU applying them, or is the color profile loaded into the monitor itself. However, having the correct ICC profile on Windows, and then switching via the KVM to Rocky did not yield the correct color match. So it’s not hardware only. And why would Color Navigator create and export an ICC profile, if it was actually applied inside the monitor. That wouldn’t make sense, and only create the risk of double applying it. So the ICC profile still is system dependent, but it could be that Rocky loaded an outdated/bad ICC profile into the monitor causing the mismatch.

I’ll have to do some more reading on how the Eizo line handles ICC profiles in this scenario.

I can try what happens when I remove the profiles entirely (assuming this is possible). The two monitors are identical models, just separate hardware. I’m not certain how different the profiles are, but assume it’s rather minimal.

I wouldn’t say that ICC profiles are a bad thing. Ultimately they’re a version of a 3D LUT that stores calibration data, applied at the OS level for most purposes. It’s simple, it makes sense for any application that is not color managed, which is 99% of them. It gets more complicated with apps that do their own color management. They should still assume that the monitor is calibrated to a standard, and since in most cases that requires the OS drivers, that’s the place to do it. It gets a bit messy if the app bypasses the OS and drives the GPU directly.

At the end of the day, folks have a wide variety of GUI monitors, and I think it’s inherently dangerous to run a broadcast monitor that is presumably calibrated, and GUI monitor that may not be hardware calibrated next to each other. So there has to be a path to take a garden variety monitor like people use, and have the image on that picture not be vastly different than what the broadcast display shows you. Otherwise it’s very distracting and hard to make good choices.

PS: The specific monitor model I’m using is ColorEdge CG2730. And in the monitor menu it’s set to Rec709 color mode, with 100cdm, 6500K, 2.4, sRGB. Yet the Rocky ICC profile while running Flame had an impact on color reproduction.