Luminous Landscape Forum

Raw & Post Processing, Printing => Colour Management => Topic started by: JRSmit on August 24, 2020, 03:08:14 pm

Title: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: JRSmit on August 24, 2020, 03:08:14 pm
HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Whether i use ACPU or Drycreek print utility, a test chart with no profile attached is now shown on display AND printed with sRGB used.
Even if i use a test chart with a profile attached like AdobeRGB or ProphotoRGB, both utilities still use sRGB.
What to do, where to look, can someone help please !?
Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: FabienP on August 25, 2020, 05:53:02 pm
I am not familiar with Drycreek print utility but ACPU should just ignore any profile and send the raw RGB values of the file to the printer driver.

Colour management on Windows is strictly done by applications and by printer drivers so I wouldn't expect the operating system to play any role in the print pipeline. The HDR mode might however negatively impact screen colour display in some cases, so SDR mode should be selected (https://www.tenforums.com/tutorials/120188-turn-off-hdr-wcg-color-display-windows-10-a.html).  The latter only applies if your monitor advertises an HDR capability.

Did you change something on the system recently, such as an updated printer driver?

Cheers,
Fabien
Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: Ethan Hansen on August 25, 2020, 06:15:10 pm
I want to make sure I understand correctly: Images are both displaying on screen and in print with an sRGB profile?

Test chart printing utilities should send image data directly to the printer without any intervening color conversions. You still need to make sure that the printer driver is not performing color conversions. Dive into the settings and verify that no color management is being performed. A quick check here is to make copies of the image with the sRGB profile assigned to one and ProPhoto to the other (crucial that the profile is assigned rather than converting to the profile!). If they print identically, color management in the driver should be off.

Windows does at times like to reset display profiles to default values. These can either be manufacturer supplied profiles or, if none were present in the display driver, sRGB. Your display calibration software can encourage the bad behavior. X-Rite's i1Profiler, for example, stores profiles as per-user settings rather than system defaults. I find more consistent behavior by storing Windows display profiles as system defaults. In the Color Management settings dialog, see if the "Use my settings for this device" box is ticked for your monitor(s). If so, uncheck the box and click the "Change system defaults" button on the Advanced tab. Choose the appropriate profile, tick "Use Windows display calibration" on the Advanced tab, and click Close more times than should be necessary to save the configuration.

Windows nonetheless still manages to lose calibration annoyingly often. We run a Powershell script triggered at both user logon and workstation unlock to reload the current calibrations.
Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: JRSmit on August 26, 2020, 12:08:50 pm
Thanks for respondent sofar.
 I had yesterday a few minutes between visits of clients in my studio, and found a curious yet not understood finding. It is Photoshop somehow. Some files have sRGB like RGB result, others not, yet in both cases the files are opened in PS without a icc profile attached accordign to PS.
Tommorow i have a bit time to dive deeper into the matter.
Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: digitaldog on August 26, 2020, 12:58:06 pm
It is Photoshop somehow. Some files have sRGB like RGB result, others not, yet in both cases the files are opened in PS without a icc profile attached accordign to PS.
Tommorow i have a bit time to dive deeper into the matter.
Untagged documents in Photoshop (and all other color managed applications) need to have some assumed color space. IF in Photoshop your RGB Working Space drop down is set for sRGB, then that's what Photoshop assumes for untagged documents. Change that to Adobe RGB (1998) and the same untagged data is assumed to be in that color space.
A target for an output profile should be untagged. A product designed for output of such targets doesn't need to know anything about nor care about the assumed or actual scale of the numbers. It simply needs to send the RGB values, as is, to the printer (driver).
Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: JRSmit on September 02, 2020, 01:58:42 am
The problem showed up in the process of saving a test chart in i1profiler to tif, then opening that tif in Photoshop. But i have done that over the past years , now i get a tif that shows the correct Lab values only when sRGB is assigned. Still looking  into it. But it is busy , luckily ;-). For the moment i continue to use colorport for my test charts for evaluating profile quality.
Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: digitaldog on September 02, 2020, 09:32:54 am
The problem showed up in the process of saving a test chart in i1profiler to tif, then opening that tif in Photoshop. But i have done that over the past years , now i get a tif that shows the correct Lab values only when sRGB is assigned. Still looking  into it. But it is busy , luckily ;-). For the moment i continue to use colorport for my test charts for evaluating profile quality.
i1P saves untagged TIFFs and there is no reason to assign anything.
Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: Ethan Hansen on September 02, 2020, 11:22:42 am
Do you by any chance have Photoshop's Color Settings->Color Management Policies-> RGB  set to something other than "Preserve Embedded Profiles" and/or the "Missing Profiles" tick box unchecked? I'm wondering whether PS is performing an behind-the-scenes color space conversion when you open the images.
Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: JRSmit on September 13, 2020, 04:06:19 am
I still have not figured out what the cause is. But it appears to be that the conversion of RGB values to Lab somehow used sRGB . Probablybstaring in my face, yet to be seen by me ;-)
Anyhow i constructed my own patch specifications, and these work ok.

Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: Doug Gray on September 13, 2020, 11:45:41 am
The problem showed up in the process of saving a test chart in i1profiler to tif, then opening that tif in Photoshop. But i have done that over the past years , now i get a tif that shows the correct Lab values only when sRGB is assigned. Still looking  into it. But it is busy , luckily ;-). For the moment i continue to use colorport for my test charts for evaluating profile quality.

A tiff chart created in i1Profiler doesn't have a colorspace as it's intended to have its RGB values directly printed w/o color management. The actual color any particular RGB value prints varies hugely between one printer and another. If you load the tif file in Photoshop it will be interpreted as having a colorspace either by a dialog that says it's untagged and asking what colorspace you want assigned to it or simply interpreting the RGB values as being in Photoshop's working colorspace depending on Photoshop's settings. Whichever happens will determine what Lab values the patches appear to have but none of that has any effect on what colors get printed by ACPU or any other process that prints the tif RGB values directly to the printer.

So if you are concerned about what the "Lab" values on a tif image of a patch set are in Photoshop you are going down a rabbit hole. They have no meaning at that point.

If you want to know what the patch set colors are when printed you create a profile from it. Then assign that profile to the patch set. Then convert the image to Lab using Abs. Col.  Now the Lab values of the patches correspond quite closely to what was printed. There is rarely a reason to do that unless you want to document what the printed image would be for that particular printer and paper.
Title: Re: HELP, all of a sudden no color managed printing on Windows 10 defaults to sRGB
Post by: JRSmit on September 21, 2020, 03:56:58 pm
I found the problem. It was me, I should have realized that the relationship between RGB and Lab is the RGB colorspace used. Even when no profile attached Photoshop has a RGB colorspace.

I use my own created testcharts, where the CIELab values are explicitly specified. One part of the testchart is a set of patches (tif file) coming from colorcheck-online.de and have been using this for years, using Colorport for measuring.

Sofar so good. But I want to start using i1profiler instead of colorport, and colorcheck-online made a i1profiler file available. So I tested that and also used it to create a testchart. (i1profiler has a different row/column structure from what I was using thusfar. But the colors did not look right, and had not the right Lab values. Turned out the RGB values used in their reference file were not what should give the right Lab values in the testchart.

So I ended up in creating a i1 profiler reference file with the right RGB values per patch(with an ID), now I can also create a testchart with i1profiler. Also the measurements with i1profiler, when saved as CIELab values are what I am used to.

So solved ;-)