Why can’t you turn off the iMac screen?
Why is there no way to turn off the screen on an iMac? I mean, properly turn it off?
It’s not something I thought about when I was thinking about buying an iMac - I just assumed it would have such a basic feature. For something that’s generally well designed and usable, this omission sticks out like a sore thumb.
I’m sure lots of people have their own reasons for turning off their computer screens. Here’s mine.
I run 3 types of nightly backups on my Mac (I’m paranoid). One does a rotating backup to DVD. One does an rsync backup to my wife’s iMac. And one does an rsync backup of our server in the UK (in case it ever goes tits-up).
And in a few months’ time, my iMac will be in the bedroom (I’m being turfed out of the office so we can turn it into a nursery for our upcoming wee nipper). So you can see why having the screen off might be a good idea. IN THE BEDROOM.
Here are the solutions I’ve heard from various people:
- Just put the iMac to sleep. Er, then how are the backups supposed to work?
- Turn the brightness all the way down. You’d think that’d work, wouldn’t you? But oh no - unlike Mac laptops, where zero brightness really does turn off the backlight, an iMac’s idea of “zero brightness” is “ever-so-slightly darker than maximum brightness”. Useless.
- Set the display to sleep in 1 minute. There are even scripts available to do this for you (and reset the sleep time back to normal afterwards).
Setting the display to sleep is not a bad approach, apart from two fundamental problems. Firstly, I don’t want the screen to turn off in 1 minute - I want it to turn off now.
Secondly - and more seriously - it’s not reliable. What I mean is, the screen spontaneously and randomly turns itself on. This seems to happen when certain specific activities occur during the backup process - spinning up the DVD seems to do it, as does network activity. (I’m still trying to pin down exactly what triggers set it off.)
As you might imagine, having a gorgeously brilliant white screen is wonderful when you’re working on it during the day. It’s not so nice when it turns itself on at 3AM in your bedroom.
So that’s the current situation. Apart from cracking open the iMac and installing a manual switch for the backlight, the best I can hope for it probably to put a towel over the thing at night. Ridiculous for such an otherwise well-designed machine. If you’re thinking about buying an iMac, and you want it doing stuff with the screen off overnight, I suggest you heed this warning. Memo to Apple: Fix this. Now.
If anyone has a decent solution, please tell me. I would absolutely love to hear it.
UPDATE May 2: Found a way to sleep the display instantly. 
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March 1st, 2007 at 5:05 pm
Hi Matt
Have you had a look at http://www.splasm.com/products/productbrightness.html ? That might do what you want. Free, and universal too, which is nice.
Nightynight might also work: http://mildmanneredindustries.com/products.html
Alternatively, you can use Applescript to go beyond what the energy saver control panel lets you do. use the following script:
tell application “System Events”
tell application “System Preferences” to reveal anchor “displaysDisplayTab” of pane “com.apple.preference.displays”
tell process “System Preferences”
set value of slider 1 of group 2 of tab group 1 of window 1 to 0
end tell
end tell
hope that helps! I would have thought that the iMac would be the least of your lack-of-sleep worries right now!
March 12th, 2007 at 11:07 am
Thanks Charles.
Nightynight just seems to do the “sleep in 1 minute” trick, which as I say, works but is not reliable - the display comes on by itself during the middle of the night (I think when the DVD backup kicks in).
That AppleScript seems to reduce the brightness to about the same level as the F14 key (ie still way too bright for the bedroom).
However, I tried Splasm’s Brightness Control and it was better than I expected - it does actually reduce the screen brightness down to almost black!
I can then do Ctrl+F8-right-right-right-right-right-down-down-return to switch to the Login Window, and it’s good to go. The acid test will be once I move the Mac into the bedroom and try it at night, but it seems pretty good. I can always stick a cloth over the top of the screen to improve matters further. Nice one 
You’re right, though - since our little 1-monther is waking us up every 3 hours anyway, the point is kinda moot right now
April 20th, 2007 at 8:38 am
Hi there!
I have kinda the same problem as you do. And those tricks you mention works for me neither.. I have my iMac connected to the TV and want to watch movies on my TV and have my iMac screen turned off.. I think this trick would help you with your problem tough: Download http://www.versiontracker.com/dyn/moreinfo/macosx/14051 double klick the icon blankscreen.saver to install. Then you just choose that screensaver and pick the “active corner..” ex. the downer left corner. And when you put your mouse there the screen goes black. And also you dont need to have the screensaver set at any time, you can have it set to “never” and it will work anyway. Hope this will help!
April 24th, 2007 at 10:47 pm
Thanks David. That’s a pretty good solution! It makes the screen go about as dark as Splasm’s Brightness Control, but without the hassle of dragging a slider around. I wonder if the screensaver will stay active even while DVD backups etc are going on? Time will tell I guess.
The screen is still bright enough to cause an eerie glow and light up the bedroom at night, but a black T-shirt over the Mac reduces it to almost negligible levels. So I guess the black screensaver combined with black T-shirt is the best solution for now!
I still can’t believe there’s no simple “screen off” switch on an iMac. Hrrumph…
August 15th, 2007 at 2:39 am
I Have Searched about and found a good programs also available as a widget called sleep display.
It Puts Your monitor to sleep at the click of a button.
Won’t solve the problem of the display awakening again but i believe this is the best we can hope for with this display.
I am still looking for a way to turn of only the built in monitor and leave my second display (the TV) on. I Don’t know if this is posable.
Hear is the link i used to get the app.
http://linestreet.googlepages.com/sleepdisplaywidget
August 15th, 2007 at 8:29 am
Thanks Russell. Yeah I mentioned this app here:
http://mac.elated.com/2007/05/02/sleep-your-imac-screen-instantly/
It’s what I use at the moment. That - and not running the DVD backup overnight - works a treat!
I thought if you plugged an external display into the iMac then the main display turns off (or at least, it can be configured to turn off in System Preferences somewhere). Is this not the case?
November 12th, 2007 at 6:53 am
2 easy steps
1) turn your screen saver to Never turn on
2) goto your energy savings setting set your display to turn off within 1 minute of inactivity
thats what i do when im trying to listen to music and what ever else it is im doing
November 13th, 2007 at 8:13 pm
Thanks for your comment Rustom. I know you can set the display to sleep in 1 minute, but the point of my post was that there was no way to sleep the display instantly on the iMac. (Though I since found a great solution: http://mac.elated.com/2007/05/02/sleep-your-imac-screen-instantly/ )
January 20th, 2008 at 5:33 am
I have been following this conversation now for a little while and I am still not finding an answer for a solution to keep the TV as a secondary monitor active (on) and have the built-in display turned off.
I have connected my TV (main floor - livingroom) to my iMac (Tiger; basement). I am using my TV with a wireless keyboard as my 2nd computer station.
Problem is: I have to keep using the Mirror-function which means my iMac is on at the same time in the basement while I am working at the TV location.
NEED SOLUTION TO MANUALLY TURN OFF BUILT-IN DISPLAY WHEN NOT USED.
Thanks in advance for any solution. It would be greatly appreciated!!!
April 7th, 2008 at 3:01 pm
If you have recent imac with leopard(2007) then you can use control+shift+(eject key) to turn off the display immediately. I don’t know if this will work on previous versions. But this will turn off all the displays (means no video out signal).
To turn off the main display and keep the external display on you can use the solution suggested by (ONLY ME?) at the following link:
http://discussions.apple.com/thread.jspa?threadID=1235392&tstart=225
Here is what he says
“…if you want to play a quicktime movie on your TV drag the movie too the TV and select Full Screen (Play Movie cool) then create in “imovie” a very small black movie only needs to be say 5 seconds long using title but with no text. Save as a quicktime movie. Now play this on your imac main screen.. pause this and make this also full screen… Hay pretso black screen..
It works and no burning screen.. “
May 10th, 2008 at 4:34 pm
Here is another option, and it has to do with Rustom’s comment above :
“2 easy steps
1) turn your screen saver to Never turn on
2) goto your energy savings setting set your display to turn off within 1 minute of inactivity”
Instead of step 2, go to System Preferences - Desktop and Screen Saver
Click on the hot corners button
Set a corner to “Sleep Display”
When you move the mouse to that hot corner, the monitor will turn off, but the CPU will remain running.
PS: to do with Arun’s comment above, I have a G5 IMac, and the keyboard shortcut works as well. Thanks for the help.
June 29th, 2008 at 8:26 am
Is there any way to easily turn the main LCD off while keeping my external monitor on.
Example:
I want to watch a movie off my 17″ Imacs (Leopard) hard drive via my 42″ LCD Flat Screen I have hooked up to it, but want to turn off my computer monitor and still have the movie play on my TV.
June 30th, 2008 at 12:10 pm
@Kevmacs: You and countless others, judging by the other comments on this post! I suggest trying Arun’s idea above as a workaround…
August 18th, 2008 at 3:02 pm
Try ctrl+shift+eject, shuts off my imac 24″ and I can use my ipod touch remote app and play different songs without it turning the screen back on.
August 25th, 2008 at 7:17 am
Hi guys,
gust bought 24 inch imac, and found this same problem - no way to switch off built in display and use only external one - e.g. LCD TV to watch movies. I mean are they really serious about it in Apple? that sucks a lot, and tricks like playing blank movies is …. (no comments). Windows drivers lets you control the video output completely, choosing which display is on. Imac seems like a toy from stone age in some respects when compared to windows - simple functions are absent!!!
September 11th, 2008 at 6:38 am
Its damn too easy… ctrl + shift + eject .. on the new Aluminium mac.. turns the display off!!
-rakesh
September 14th, 2008 at 8:20 am
Hi rakesh,
Check the date of this blog post - February 2nd, 2007. Sleeping the display is a Leopard feature.
It’s great that you can now do this, of course.