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In Canon Digital Photo Professional v4, there is a setting in Preferences | Color management named "Color matching settings" with a group of options "For display". They are:

  • sRGB
  • Use the OS settings
  • Monitor profile

Does selecting "Use the OS settings" mean that DPP will apply the color profile a second time on top of what Windows does?

Here's another way to think of the question.

  1. Take a high quality IPS monitor and plug it into a Windows 10 computer.
  2. Make a perfect ICM file from a color calibrator.
  3. Apply the ICM file using Windows's "Color Management" dialog and confirm that all the colors on the display change a bit after applying them.
  4. Run Canon DPP with "Use the OS settings" selected
  5. Look at a photo.

Should the colors all be wrong because the ICM file is being applied two times (once by Windows and once by Canon)? Or are all the colors correct because Windows does not affect the colors displayed by Canon DPP (unless "Use the OS settings" is selected)?

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    \$\begingroup\$ Related: basically the same question for Linux (with GIMP and GNOME) \$\endgroup\$
    – mattdm
    May 13, 2019 at 1:11
  • \$\begingroup\$ Thank you for your comment that breaks down what the OS does vs. the application. \$\endgroup\$
    – Zian Choy
    May 13, 2019 at 7:27

2 Answers 2

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Color management is a chain with several different links. Each link needs its own profile.

The 'For Display' setting in the DPP 4 [Preferences → Color Management] section that asks about monitor profile affects how the computer's graphics adapter sends colors to the monitor. It has no effect on the inner workings of DPP 4 itself.

If you select 'Use the OS setting', the same monitor profile will be used that is used by default based on your system's settings. If you have used a hardware/software calibration tool and are using that profile as the system default (which is what most of us do), then leaving DPP 4 set to 'Use the OS setting' will continue to use that profile to compensate for the measured output of the monitor.

If you select another option, DPP 4 will instruct the graphics adapter to use the specified monitor profile choice in place of the default OS profile for the monitor, not in addition to it.

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  • \$\begingroup\$ Your post and mattdm's comment help me a lot. Now I understand that Windows doesn't apply all the bits of the ICM file and DPP still has a role to play. In reality, I don't have a perfect ICM file so I'm off to figure out if my color calibrator is perishing, getting tricked by my monitors, my monitors are dying, or all of the above. \$\endgroup\$
    – Zian Choy
    May 13, 2019 at 7:27
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I don't have first-hand experience with DPP4, but I'm reasonably sure it won't do double correction.

From what I know, the OS doesn't blatantly do colour correction to any output. It offers a service to do that and needs to be asked explicitly. Some software use this service; some (often higher-end one like Photoshop) have their own engine, but usually they still use the ICC profile installed in the OS.

The 'Use the OS settings' option, I guess, either uses the OS for colour correction, or gets the conversion matrix from the current monitor profile installed in the OS.

The 'Monitor profile' must ask the user which exactly profile should be used. If you pick the same profile as the one currently installed, the result should be identical to the previous option.

sRGB is just a generic profile that could be used if the system is unknown and has never been calibrated.

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