Colour management warning for dual display users

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Colour management warning for dual display users

For those of you who require a colour managed workflow and have more than one display, be very careful in Mountain Lion. It appears to have a bizarre bug where images loaded and shown on the primary display (e.g. in Preview) are initially rendered with the colour profile from the secondary display, or something along those lines. Dragging the display window to the secondary display and back again sorts things out. I've filed a bug report.

If your two (or more) monitors have the same colour profile, you won't have a problem. The only workaround I can see is to set your least important display(s) to all have the same profile as your (probably calibrated, if these things matter to you) primary display, at least until (if?) the bug gets fixed.

If you want to see it for yourself, set your two displays to differing profiles - e.g. NTSC (1953) on the primary and Wide Gamut RGB on the secondary. Then load an image into Preview - something with lots of shades of red "works" well for the colour profiles mentioned. Take a screenshot of the Preview window as a reference. Move the window to the secondary display; note the colour shift as it gets re-rendered. Now drag it back to the primary display. It'll look quite different compared to the screenshot you took earlier, despite the fact it's the same image being shown by the same application on the same display in the same window... All you did was drag the window between two monitors and back again.

It doesn't seem to matter if the image in question has a colour profile embedded in it or not. When comparing with your screenshot, feel free to drag the screenshot between the monitors too - after all, it'll be suffering the same rendering bug! You'll still see a different result; in fact it may even be magnified by the accumulated rendering errors.

Preview isn't the only application affected; I've seen identical issues under harder to replicate circumstances in Safari, for example.

Given this fault and others I've seen with colour rendering in Lion, plus several new bugs found in Mountain Lion, I'm afraid that if a colour managed workflow is important to you - well - Snow Leopard or Windows...?! Ugh, what a mess 😟

Posted on Aug 2, 2012 12:33 PM

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Answer 1

Aug 5, 2012 11:38 AM in response to Pond

I've encountered many of the same woes with color management being a graphic designer, but here's my issue:

Have a 15" (Early 2011) Macbook Pro. It is turned on with me hooked up to my Dell U2410 and display open for a dual display configuration. The Dell is my primary monitor.

I then unplug my MBP to use it around the house. I go to plug it back into the Dell for my dual monitor. I notice that the color on the Dell looks good, but now the MBP has a very blue color temperature. Like moving from the preconfigured 'Color LCD' profile to 'sRGB' which definitely shifts to a blue color on the MBP.

I check the color profiles in System Settings and the Color profiles are correct. 'Dell U2410' for my Dell and 'Color LCD' for my MBP. But as I said, it's much bluer than standard. I try to change the color profiles around on the MBP and no matter which I select it's always the same color with no shifts I would expect to see.

Only solution I have found is to restart my computer. Upon restarting all is well again in the world.

It's pretty annoying having to restart my computer everytime I plug it back into my workstation with Dell and keyboard.

Related note: USB does not work when I plug things back and again have to restart to fix this.

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