zoeycs

Q: adjust brightness on second and third monitor on iMac setup

Just bought a new IMac and put my old second and third monitors to it. All is well but I want to adjust the brightness of the seond and third monitors and I can't seem to do it. The controls only seem to work on the IMac display. Thanks, Ed.

iMac, OS X Mavericks (10.9), Other 2 monitors are old Cinema HD

Posted on Dec 14, 2013 3:27 AM

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Q: adjust brightness on second and third monitor on iMac setup

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  • by Delgadoh,

    Delgadoh Delgadoh Dec 16, 2013 8:05 AM in response to zoeycs
    Level 4 (1,405 points)
    Dec 16, 2013 8:05 AM in response to zoeycs

    Hey zoeycs,

     

    I found the following information on adjusting the brightness level on Cinema Displays:

    This software updates the System Preferences pane where you can change Ambient Light Sensor settings. Enable the option "Automatically adjust brightness as ambient light changes" to turn the ambient light sensor on and off. Use the slider to adjust the brightness level. 


    Note: You must have the cinema display's USB cable connected directly to your Mac to access this functionality.


    via: About the 27-inch LED Cinema Display Software Update 1.0

    http://support.apple.com/kb/HT4293

     

    I would try to connect the display's USB cable to your Mac and then try adjusting the brightness to see if that works.

     

    Welcome to Apple Support Communities!

     

    Sincerely,

    Delgadoh

  • by zoeycs,

    zoeycs zoeycs Dec 26, 2013 2:33 PM in response to Delgadoh
    Level 1 (0 points)
    Dec 26, 2013 2:33 PM in response to Delgadoh

    I have the USB connected and I open the Display window and enable the Automatically Adjust brightness, but the slider only affects the iMac window, makes no difference to the other windows. Both the other windows get their own Displiay window in them, but they do not have any options for the brightness or a slide bar. They are effectively useless. Thanks for trying, Ed.

  • by nirvanadude220,

    nirvanadude220 nirvanadude220 Apr 29, 2016 6:59 AM in response to Delgadoh
    Level 1 (4 points)
    Apr 29, 2016 6:59 AM in response to Delgadoh

    This worked perfect. Just had to close and reopen System Preferences and it took.

    Been working with a dim third monitor for over a year - thanks!