How to set color bit depth

Question

Level 1

8 points

How to set color bit depth

I am getting feeling that changing color bit depth of the display is not possible. Or am I wrong?

I am using external VGA display that I know is capable of displaying 24-bit colors. Last night I used projector so I disconnected the monitor but when I plugged it back today it shows 16-bit colors (I can see color banding on my background.)

Is there a way to fix it? I tried reconnecting the display but without any luck. I am aware that resetting PRAM may help but I am quite surprised that there is no easier way. I don't want to install 3rd party software to handle this (such as SwitchResX).

Maybe there is some terminal command or something? Please help me.

(Don't use universal answer "Take it to Genius bar" because A) We don't have them in my country B) It's such a silly thing it must be fixed somehow).

Posted on Jul 28, 2011 2:20 PM

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Answer 1

X423424X

Level 6

14,271 points

Jul 31, 2011 1:07 PM in response to comatory

Sorry, it was getting late when I answered. So I guess if you are looking for some provision already provided to set the depth on current versions of OS X then the answer must be no, you can't.

Maybe you can figure out a way to change the EDID info for the display. I know how to display EDID but I don't know how to change it. I'm assuming there must be a way since SwitchResX can do it. Below is a terminal command to display the EDID info:

ioreg -l -w0 | grep EDID

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Answer 2

comatory Author

Level 1

8 points

Jul 31, 2011 2:12 PM in response to X423424X

Thanks for reply.

OK I will probably reset PRAM, it seems the only way for me. I'm quite disappointed with that, maybe it's the VGA output that causes my computer to never "estimate" the right resolutions when I switch outputs (TV, projector).

This is my first time I'm really disappointed with OS X.

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Answer 3

Jul 28, 2011 3:27 PM in response to comatory

Under System Preferences>Displays>Display Tab>Color:Millions.

That ought to do it.

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Answer 4

comatory Author

Level 1

8 points

Jul 29, 2011 12:39 AM in response to Joxer The Mighty

There is no color option under Display Preferences > Displays tab. There is only Color Tab where I can calibrate display or choose a color profile. I am running 10.6.8.

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Answer 5

X423424X

Level 6

14,271 points

Jul 29, 2011 1:55 AM in response to comatory

There's a menu option in SwitchResX to allow you to do this (256, thousands, millions) but I don't know if it actually works.

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Answer 6

comatory Author

Level 1

8 points

Jul 31, 2011 4:05 AM in response to X423424X

Please read my original post. I don't want to buy another application to do a basic job.

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Answer 7

X423424X

Level 6

14,271 points

Jul 31, 2011 2:16 PM in response to comatory

One final suggestion on all of this. When you reconnect these various displays try clicking Detect Displays in the displays preferences and see if that fixes anything up.

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