Cinema Display Blues

September 5, 2008 7:10 AM

DisplayColorFilter. Two Apple Cinema Displays on one Power Mac. One display has a blue color cast. What do I do?

I'm running two Apple Cinema Displays on a MacPro. Both displays were purchased at approximately the same time (they are the same make, model, generation, etc.). One has a slight but noticeable bluish color cast that I'd really like to get rid of. All the settings in ColorSync are the same, as are the settings in monitor preferences. I've switched ports, checked connections, re-calibrated. I would try to manually fix the colors of the bluish display, but all the controls look forbidding. I don't know where to start. Can I get rid of the blues, or is my monitor broke?

posted by MarshallPoe to computers & internet (9 comments total)

Have you also tried switching cables? I once had a nice monitor that had a green tint in the display, but it turned out to be a bad wire in the video cable. When I swapped it out, everything worked fine.

Since you have two monitors, it should be easy to swap cables between them to see if that clears things up.
posted by tomwheeler at 7:28 AM on September 5

When you say calibrated, do you mean you used monitor calibrating hardware and software or do you mean you calibrated "by eye"? That will make a difference. Barring any defects in the monitors or video card, monitor calibration with something like the i1Display 2 or something similar will get you accurate color.
posted by eatcake at 7:36 AM on September 5

Definitley calibrate your monitor in expert mode - it helps to squint your eyes while you drag the sliders to make the apple images match the horizontal lines. Don't worry, it's unlikely that you're going to screw your monitor's color up much worse than it currently is.

I'd keep the gamma at 1.8 (standard Mac gamma) and the important part of the calibration for you is selecting your target white point. I would drag the slider until the blue goes away (it should). If it doesn't, you've got a hardware problem (a bad cable, bad connection, bad monitor or bad graphics card).

If the problem persists, try switching the monitors around and see if the "blue" hue jumps to the other monitor. If the hue appears on the other monitor, that will rule out a bad monitor. You can try swapping the monitor's data cables to further pinpoint your issue.
posted by plasticbugs at 7:36 AM on September 5

This may sound like a stupid question, but in all seriousness have you tried unplugging it and plugging it back in?
posted by fusinski at 7:56 AM on September 5

I'm exposing my nerdiness here, but open a Terminal window and run

/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/DMProxy

It may help. It may not.
posted by cmiller at 8:34 AM on September 5

Specifically, you want to make sure both monitors have the same color temperature. 6500K is considered standard for photography and video editing work.
posted by zsazsa at 8:45 AM on September 5

Calibrate it with a hardware calibrator (I use the fairly inexpensive Pantone Huey, works great).

You will never get it right trying to do it with your eyes, it's just not possible because of the way we perceive color.
posted by bradbane at 10:08 AM on September 5 [1 favorite]

Definitley calibrate your monitor in expert mode - it helps to squint your eyes while you drag the sliders to make the apple images match the horizontal lines.

Quoted for truth. Also, defocusing your eyes works well. Pretend you're looking at one of those "magic eye" pictures.

Calibrate each monitor separately, but make sure they have the same whitepoint/color temp, as zsazsa points out.
posted by lekvar at 12:25 PM on September 5

There's an odd test I'd like you to try that may help determine whether this is a color profile issue or a hardware issue. Boot your Mac with the Option key held down. This will bring up a selection screen that lets you pick which drive to boot from. Do nothing, just look. Both monitors *may* be on at this point, showing something akin to a gray background. If they are both on, and showing a gray background, is it the same color or is one of them blue-tinted?

If the answer is "yes, one of them is blue-tinted", then swap the monitors and try again. If the same monitor is still blue-tinted, then *one* of your monitors is not producing the correct temperature backlight.

If the answer is "no, they're both gray", or if the blue tint shifts to the other screen when you swap the monitors, it's either the Mac Pro or OS X causing it. Try this:

A) Open the Displays preference pane. On each monitor, go to the Display tab and set the Brightness to full strength, then go to the Color tab and ensure that they're using the same profile. Does this fix it?

B) On each monitor, go to the Color tab and uncheck "Show profiles for this display only", then select "Apple RGB" or "sRGB" or "Adobe RGB (1998)". Make sure the same profile is selected on both monitors. Does this fix it?

If these two steps don't fix the issue, one of your monitors is likely producing the wrong color light.

Apple Cinema Displays do not have hardware white point and color temperature controls. The monitor is fixed to certain values at the factory and then calibrated exclusively through the color profiling software used by the operating system. They should be set to the precise same white point, so if they're not, that's actually something that needs to be repaired by Apple.

One solution to all this is to take both displays AND your Mac Pro to an Apple Store and tell them that one of your monitors has a blue cast, and you need the Genius Bar to fix it. Call ahead *before* you take a hundred pounds of equipment into the store. If they fail to fix it, they should be able to set up a hardware repair for you.

Normally I would advise you to use a huey for calibration but if you have two Cinema displays of the same model, their color temperature is SUPPOSED to be precisely calibrated at the factory to a single, set value, and they should look precisely the same when using the Apple Cinema mumble Display profile that's shown in the Color tab under Displays preferences. If the backlight in one monitor has gone south and is no longer producing the correct temperature light, then a hardware calibrator such as a huey will help compensate.
posted by crysflame at 6:22 AM on September 6