AdobeRGB(1998) not consistent between Photoshop and PI

[peresanz]

Hello Juan,

 I've noticed that an image saved from Adobe Photoshop CS with the AdobeRGB ICC color frofile included, looks different when opened with PixInsight. It appears to have a blue cast in PixInsight. If I choose the "image"  menu and select "information", the ICC color profile  shows correctly in the information frame.  In the "Edit" -> "color management setup..." I have also selected AdobeRGB as the default profile.

 Any clue about why the image shows different in Photoshop and Pixinsight?  

Thanks Juan, and congratulations for all this work.

Pere Sanz

[Carlos Milovic]

Hi!

What happens if you disable the Color Management in PixInsight?
Have you calibrated the monitor (i.e. create the monitor's profile with Adobe Gamma, or another application)? Wich are your working parameters in PI's Color Management? Is the monitor's profile correct?

[peresanz]

Hi Carlos,


What happens if you disable the Color Management in PixInsight?

Opps! The color cast disapears and the view is matching the one in photoshop. It looks right.


Have you calibrated the monitor (i.e. create the monitor's profile with Adobe Gamma, or another application)?

Yes. I calibrated the monitor with Adobe Gamma, saved the monitor profile as "pere" and Adobe Gamma Loader loads this profile when i start the computer as the default profile.

 Wich are your working parameters in PI's Color Management? Is the monitor's profile correct?

This looks somewhat odd: In the "Color Management Setup" menu, the Monito Prifile displays as:

 Colorific Relative: Philips 107B Gamma: 1.0 Temp: 9300

Which is my monitor but I'm not sure if this is the calibrated profile or the originar one. Actually, I cannot change this profile.

Thanks for helping,

Pere Sanz

[Carlos Milovic]

Hi Pere

Hmmm... defitively it is an issue of the Color Management. Franckly, I don't know the source, so we have to wait Juan's answer. I don't fully understand how it works...

Anyway, just try something. When we run Adobe Gamma, the screen's appearence changes, right? In your case, does it becomes a bit bluer? Before you run PixInsight, close Adobe Gamma, and then compare the results. I'm just guessing a possible cause... it might not work right at all.

Tell us what happens this time. =)

[Anonymous]

Hi Pere,

OK, you've found a bug!

... and I've fixed it, after a night of hard bug hunting work and some 2500 lines of code deeply revised...

In PixInsight, special LUTs (look up tables) are used to speed up color transformations between different color spaces (i.e., from the ICC profile space of the image to the monitor space) for screen renditions.

Each LUT has 256 entries, and each entry says how an individual 8-bit raw color should look like when represented on the monitor.  PixInsight builds these LUTs automatically for each image window according to ICC profiles. The bug is here: some LUT elements are wrongly calculated, which is causing improper renditions of color managed images on the screen. In general, this error tends to show blue casts and excessive color saturation; I don't know why... and I don't want to know!

Note that this bug affects renditions on the screen exclusively. Color management transformations applied to actual pixel values (with the AssignICCProfile process) work correctly, so if you've transformed images with PixInsight you can be sure the results are numerically correct (up to MS's ICM 2.0 accuracy).

You probably don't imagine all the work and headaches you've avoided me. Yesterday I was almost ready to release new version 1.0.1 when I read your bug report. Fortunately, the new release will come with this horrible bug fixed.

Thank you very much!

Juan

[Juan Conejero]

For some reason (a bug in myself?) I was not logged-in when I wrote my previous reply. Well...   8)

[peresanz]

Hi Juan,

 Is there any bonus pack for the first one to find a bug? (kidding :-))

 I can perfectly figure out how hard it can be to find a nasty bug in the last minute previous to release a product (I work as hardware/software developper and know this kind of stress).
  I can't wait to see what new features are included in the new release! I will keep in front of the computer waiting for ...

Cheers,

Pere

[Juan Conejero]

What happens if you disable the Color Management in PixInsight?

Opps! The color cast disapears and the view is matching the one in photoshop. It looks right.

In my previous reply I've explained what actually is happening. If your image has the AdobeRGB(1998) profile embedded, you MUST have color management enabled in PixInsight, Photoshop, and any other application capable of color management.

In PixInsight 1.0.0, the problem is the bug you've detected. Having fixed this bug, in release 1.0.1 hopefully color management will be 100% consistent with PS.

Wich are your working parameters in PI's Color Management? Is the monitor's profile correct?

This looks somewhat odd: In the "Color Management Setup" menu, the Monito Prifile displays as:

 Colorific Relative: Philips 107B Gamma: 1.0 Temp: 9300

Which is my monitor but I'm not sure if this is the calibrated profile or the originar one. Actually, I cannot change this profile.

If PixInsight's Color Management dialog says this, it's because this is the monitor profile currently assigned to your monitor in your Windows. This profile has been generated by (or is part of) the Colorific calibration utility that comes with most Philips monitors.

From the profile signature, it seems that you're working at 9300 K color temperature and gamma=1.0 (linear). Is your monitor a LCD monitor? If it's a CRT monitor (AND the 107B is a CRT), I'd bet these parameters are completely wrong. I don't know of any linear CRT; usually CRTs have gamma=2.2. The 9300 K temperature is also quite incorrect for imaging work except you're doing just plain web production. No printer or proofing device works at such high temp.

If you don't have a reliable calibration device, I recommend you to select the sRGB IEC61966-2.1 standard profile for your monitor. It just works well if you don't have anything better. Also I suggest working at 6500 K (daylight), if your monitor allows you to adjust color temperature (I'm almost sure the 107B does).

To change your monitor profile, right-click on the Windows desktop and select Screen Properties > Configuration > Advanced Options > Color Management. If you remove all profiles here, Windows will use the default sRGB color space for your monitor and all will be fine. Or try running Colorific again if you like the hard way...  

[Juan Conejero]

Hi Juan,

 Is there any bonus pack for the first one to find a bug? (kidding :-))

 I can perfectly figure out how hard it can be to find a nasty bug in the last minute previous to release a product (I work as hardware/software developper and know this kind of stress).
  I can't wait to see what new features are included in the new release! I will keep in front of the computer waiting for ...

Cheers,

Pere

Well, perhaps we'll create a "Hall of Fame" one of these days  :lol:

Indeed we have very skilled bug hunters here (Carlos, are you listening?   )

For now, add ten points to your personal account ...  :wink:

[peresanz]

Hi Juan,

From the profile signature, it seems that you're working at 9300 K color temperature and gamma=1.0 (linear). Is your monitor a LCD monitor? If it's a CRT monitor (AND the 107B is a CRT), I'd bet these parameters are completely wrong. I don't know of any linear CRT; usually CRTs have gamma=2.2. The 9300 K temperature is also quite incorrect for imaging work except you're doing just plain web production. No printer or proofing device works at such high temp.

When I run Adobe Gamma and follow the step by step (wizard) calibration, for any reason the profile above is selected automatically as starting point for calibration. In the next steps I have confirmed that gamma is set to 2.2 and temperature is set to 6500 K. The result of calibration is saved in a file with extension ".icm". My guess is that despite of the name of the profile signature, the monitor is well calibrated.

Pere


 [/quote]

[Juan Conejero]

My guess is that despite of the name of the profile signature, the monitor is well calibrated.

Might be. To make sure, download and install ICC Profile Inspector by Huan Zeng of Hewlett Packard:

http://www.color.org/membersonly/profileinspector.html

To download, click the link "Click here for the ICC Profile Inspector" at the bottom of the page.

With ICC Profile Inspector you can see the entire contents of any ICC profile. Load the .icm file and click the TRC tags to see the transfer curves for each channel. You'll get a graphic where you can read the gamma value used.

Regards,

Juan

[peresanz]

With ICC Profile Inspector you can see the entire contents of any ICC profile. Load the .icm file and click the TRC tags to see the transfer curves for each channel. You'll get a graphic where you can read the gamma value used.

 Nice application!  Gamma values for the three channels read  2,199

Cheers,

Pere

[Niall Saunders]

Hi all,

Whilst browsing around in some of the (very much) older Forum posts, I came across this one, which seemed to have a useful link, but which, unfortunately, no longer worked.

A quick 'Google' served up this alternative - for those who may be interested

http://www.color.org/profileinspector.xalter

Cheers,

[Juan Conejero]

Thank you for the update Niall. I wasn't aware of a new version of ICC Profile Inspector.

It seems that this version can edit profiles. Literally, it says "Profile Inspector also incorporates the ability to modify many of the tag entries in a profile." I wonder if this little program can be a valid solution for those that suffer from incorrect monitor profiles generated by some calibration systems, especially on the Mac. I'll make some tests when I get a bit of time.

By the way, as you can see, PixInsight is an "ICC Version 4 ready" application

To verify:

- On the ICC page you have linked, click on the "Is your system v4-ready?" link on the right-hand column.

- Click the "one in HTML" link. Here is a direct link to the page in question.

- If your browser doesn't implement color management (or has it disabled), the image will look funny. Right-click on each quadrant to save the corresponding JPEG images to your hard disk.

- Open the four quadrant images in PixInsight, and note how they look perfect (assuming you have not disabled color management). You can press F11 to enable/disable color management for each quadrant, and see the difference. PixInsight fully supports version 2 and version 4 ICC profiles.