Can I change the brightness on a secondary display?

Question

I have a MBP with a secondary display. Is is possible to have the brightness keys (F1 & F2) change both the main display (laptop screen) and the secondary display (a VGA external monitor connected via a Thunderbolt port with an adapter)? If not, is it possible to change the brightness on the secondary display?

Answer 1

One of my favorite tools for doing this is Shades which is "donationware."

You can adjust each monitor separately, and set keyboard shortcuts for them as well.

If you want a command line solution, I found brightness.c which compiled cleanly using:

gcc -std=c99 -o brightness brightness.c -framework IOKit -framework ApplicationServices

(You'll need Xcode to be installed to compile it. If you want a precompiled version, mine is available here http://luo.ma/attic/brightness.bz2.)

It will let you set the brightness for either monitor.

Answer 2

If you press CTRL and F1/F2 the brightness on a secondary display will adjust. (Test on my MacBook Air 2011 13" and 27" Thunderbolt Display)

Answer 3

Unfortunately, Macs don't have access to an external display's brightness settings. On most displays, that is only controllable using the physical buttons/menus on the display itself.

I agree that this would be a great feature to see, but it isn't really possible now to control brightness over the video cable.

Note that I can't speak for Apple's Cinema Display and Thunderbolt; I haven't tried that and it may be different.

Answer 4

If you're using an Apple Cinema Display it is possible to control brightness as long as you connect the display's USB cable to your Mac. The causes a "Brightness" slider to appear on the screen's control panel in "Displays" System Preferences. Unfortunately the F1 and F2 don't change the brightness settings on the external screen.

Answer 5

If you have an Apple Cinema display and are adjusting brightness via the "displays" preference pane, note that the preference pane will show up both on your main display (the cinema display) and on the MBP. It allows you to set the brightness separately.

Answer 6

If you press CTRL and F1/F2 the brightness on a secondary display will adjust. Tested and works on my MacBook Pro (Early 2011) 15" and 27" Thunderbolt Display.

Answer 7

I have two screens connected to my Mac pro. (This also works for macbookpro.) I have the USB on the first screen connected to the Mac. The second screen has its USB connected into the back of the first screen (the 2nd screen display adapter uses an extender to get to the Mac - you could likewise use a USB extender to get to the back of the mac).

With both screens communicating to the mac via screen as well as USB, F1 and F2 as brightness control the dimming of the first display, control plus F1 and F2 control the second screen. No need to disconnect at all.

Answer 8

I have 2 thunderbolt displays connected to my MBP. I had to connect only one display at a time in order to adjust the brightness. Then I reconnected them both and all was well. Too bad the control panel doesn't show the brightness slider on both displays but this is a simple solution.

Answer 9

Screen Dimmer isn't free ($2), but is the only tool I could find that handles multiple monitors (up to 3).

Seems nice and elegant the short time I've used it. Sits in menubar, and has a simple slider and monitor selector, as well as keybindings for brightness increase/decrease.

My 3 external displays are non-apple (1 Dell with displayport, 1 samsung with displayport->dvi, and 1 old acer 19" with hdmi->dvi) on a MacBook Pro Retina 15" with 10.8.2.

edit: For the OP's question this shouldn't matter, but fyi for 3 monitors - it seems to only allow one combination of monitors for dimming (i.e. can't dim completely separately -- this works for me as I use it to dim the 2 side monitors so they don't distract from the main middle monitor)

Answer 10

If you run Windows Vista, Windows 7, or Windows 8, you can adjust brightness easily with Mac Brightness Control utility.

Answer 11

There are many answers here, but one wasn't mentioned (though it only has limited applicability---you need to have a second keyboard handy.) When I have a second display hooked up to my MBP, and a second keyboard plugged in, then the built-in laptop keyboard's function keys control the built-in (main) laptop LCD and the external keyboard's function keys work for the secondary.

In case it's changed, this is on 10.6.8.

Answer 12

i have solved this little riddle for u. After experimenting with lots of hot keys (and bare with me, as this is not the most practical, but it is quick once you get the hang of it) I am using a duel screen Imac 27inch to thunderbolt 27inch via thunderbolt connection.

ok so here is the commands....

cmd § F1 (screen will duplicate on 2nd screen)

now you can dim the 2nd screen (F1)

repeat... cmd § F1 (screen will revert to last and still be dimmed)

now you can dim the Imac screen!

Hope this has helped and share the word!

Let them know

Walziee