How to turn off iMac screen but leave secondary screen on?

[makrom]

I found the easiest solution

Download a black picture on google Images. Make it full screen on your iMac display and lower the brightness all the way. Drag whatever you want to your external display and Enjoy.

I made this account just to answer this question for anyone who's wondering for the future.

Showing a black image isnt the same as turning a screen off. The back light will still power through the whole time and show wear if done excessively. Furthermore, showing a black image is the most straining a conventional LCD can do, since the transistors are set to absorb all the light. True, this shouldn't be too relevant for LCDs, but should absolutely be avoided for LCDs with a high light density (such as projectors).
It is a simple solution, but the result isn't ideal (unless you use an OLED panel, in that case it's virtually equivalent to turning off the screen).

edit: just noticed that this thread isn't exactly new.

 

[Amazon07]

YES. This was simple, free and worked perfectly. Thanks!

I'm sorry if I am doing something wrong, but I went on this link and clicked on 'Download', but after downloading it nothing happened and when I click on the download, nothing happens! What am I doing wrong? Sorry, I'm not a huge expert just would like to be able to turn off my iMac's screen and watch stuff from my iMac on a flatscreen TV My iMac is a 2009 model. Thanks!

 

[Amazon07]

External Monitor on iMAC

Install the DisableMonitor app from:
https://github.com/Eun/DisableMonitor

This allows you to enable/disable the two monitors independently as well as set their resolution

I'm sorry if I am doing something wrong, but I went on this link and clicked on 'Download', but after downloading it nothing happened and when I click on the download, nothing happens! What am I doing wrong? Sorry, I'm not a huge expert just would like to be able to turn off my iMac's screen and watch stuff from my iMac on a flatscreen TV My iMac is a 2009 model. Thanks!

 

[bent christian]

I use a hot corner to disable the screen. It does not require installation of an additional application. I have it set up to go to screen saver if I drag the cursor to the lower left, the monitor goes to sleep if I drag to the lower right. I only use one screen, but this seems like it should work to blank out one monitor on a dual set up. Theoretically, each should have their own set of corners.

 

[JonnyBlaze]

dying to know the answer to this. hot corners doesn't work as it turns off both displays when I've tried it. Have gone for a black screen but not really what i want. gonna try the disableMonitor app....hope it works!

 

[Dreadnought]

I'll say it again, use an AppleTV and you're done!

 

[JonnyBlaze]

While agree that an Apple TV might be one solution, I don't want to have to buy something else...I just want to be able to turn the screen off occasionally. Didn't figure that would be so hard iMac when it was so simple on my 2008 MacBook! Haven't got around to trying the above app, but here's hoping.

 

[nicho]

I use a hot corner to disable the screen. It does not require installation of an additional application. I have it set up to go to screen saver if I drag the cursor to the lower left, the monitor goes to sleep if I drag to the lower right. I only use one screen, but this seems like it should work to blank out one monitor on a dual set up. Theoretically, each should have their own set of corners.

nope.

 

[AppleNewton]

While agree that an Apple TV might be one solution, I don't want to have to buy something else...I just want to be able to turn the screen off occasionally. Didn't figure that would be so hard iMac when it was so simple on my 2008 MacBook! Haven't got around to trying the above app, but here's hoping.

Well MacBook's operate and power a bit differently, while it would make sense to consolidate the options for the iMac...the best bet is to just do an AppleTV to save wear and tear on your display...who knows how well or long those software hacks will work or damage they could cause the system.

 

[nicho]

While agree that an Apple TV might be one solution, I don't want to have to buy something else...I just want to be able to turn the screen off occasionally. Didn't figure that would be so hard iMac when it was so simple on my 2008 MacBook! Haven't got around to trying the above app, but here's hoping.

you could always try to fold your imac?

 

[JonnyBlaze]

you could always try to fold your imac?

haha, could work, but would be a fairly permanent solution to turning the display off I would imagine, and anyway seems that unlike some iPhones, the iMac just isn't bendy...

 

[colnago1331]

I'm sorry if I am doing something wrong, but I went on this link and clicked on 'Download', but after downloading it nothing happened and when I click on the download, nothing happens! What am I doing wrong? Sorry, I'm not a huge expert just would like to be able to turn off my iMac's screen and watch stuff from my iMac on a flatscreen TV My iMac is a 2009 model. Thanks!

After clicking on the download you should have a zip file. Open/extract that and you'll have a "DisableMonitor" application file. Open that and you should have a monitor icon in the upper right of your screen. You can use that to turn of your iMac's screen. It worked for me, and I've got a late 2009 iMac.

 

[vkd]

One would have thought that the Energy Saver options in System Preferences could be used to turn off the unused iMac screen. I do not have more than the one iMac screen available to test but I do know that audio playing from any source will continue whilst the screen obeys the Energy Saver settings. Thus, in theory, if all screen activity is taking place on a second screen and the iMac built-in screen does not register activity for the set period, it will sleep.

 

[nicho]

One would have thought that the Energy Saver options in System Preferences could be used to turn off the unused iMac screen. I do not have more than the one iMac screen available to test but I do know that audio playing from any source will continue whilst the screen obeys the Energy Saver settings. Thus, in theory, if all screen activity is taking place on a second screen and the iMac built-in screen does not register activity for the set period, it will sleep.

it's all or nothing without third party tools.

 

[daycaesar]

I'll say it again, use an AppleTV and you're done!

I've tried this with my MBP last year and it seems to go to 720p as the max res. I think perhaps a newer apple tv can do 1080p but when you have a 1440p monitor well it kind of defeats the purpose... or if you have a 4K, etc.

I just bought (being shipped) a BenQ 32" screen that is 1440p and I want to hook it up to my iMac 27". The iMac has cracks in the glass which don't really bother me but I just want an iMac 32" but not at 720p or even 1080p. Maybe if I wasn't using it as a monitor that would be different but I do graphic design, etc.

I think I am just going to dim the screen and put the BenQ in front of it. Not sure if that will work or not. If not I am going to try the screen disabler... I'm running El Capitan or whatever so who knows if it will still work. Or I could perhaps use both monitors side by side... but I would still want to be able to turn the iMac display OFF.

 

[asv56kx3088]

Dying to know the solution too, I have a setup of Macbook with an external monitor. My temporary workaround is to enable display mirroring and dim the display on my MacBook.

 

[nicho]

Dying to know the solution too, I have a setup of Macbook with an external monitor. My temporary workaround is to enable display mirroring and dim the display on my MacBook.

Ugh you can just close the lid and use it in clamshell mode.

The reason op or anyone else in the thread couldn't do this is because they had iMacs.

 

[dragos_1999]

What are you using to watch video with? VLC has an option to blank the other screen during playback...

Best solution. Thank you.

 

[Trimorphous]

I'm sure this should be simple but I can't figure it out.

I have my iMac connected to my TV and am using Plex to watch stuff on the TV.

What I'd like to do is turn my imac screen off without turning off the second monitor output (i.e. tv) as the imac screen is a bit bright/distracting (even on lowest brightness) when watching in the dark.

Anyone know how to do this?

There is an app on the app store now called Screen Commander which blanks the screen, I need something as I'm getting pixel ghosting when the iMac screen gest hot. As I use my ultrawide most of the time it seems pointless risking more damage.

 

[Trapantski]

YES. This was simple, free and worked perfectly. Thanks!

I've bought a Cintiq Pro 32 Touch Pen Display and now need to get a new mac to power the thing. I'd like to get an i9 iMac, but with only an 8GB Vega GPU option being useful, I'm worried too much of this power will be directed at the apple screen display and not go directly to my Cintiq Pro screen. Does the above Github fix limit the GPU use of the screen?

 

[ajmichmac]

toss a thick dark towel over the mac screen (low tech but hey)