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By iiAtlas

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Having two monitors on OSX is both a joy and a pain. Simple things like viewing a movie or playing a game quickly become a hassle when you have one screen playing and the other blasting full brightness your face. There is no quick and easy way to "cover" or dim a single screen, so I got to work on a solution...

The result is what I am creatively dubbing "ScreenDimmer." It allows you to selectively dim up to three monitors in all sorts of configurations and opacities (brightnesses), while not interfering with your other applications. You could choose to have your second monitor be dim while your primary plays a movie, or maybe have your primary and third be full black while you play a game on your second. The possibilities are endless! Some of you with single monitors may also find this little utility useful as it will give you more "fine grained" control over your brightness.

I initially created this small utility for myself but it evolved into something that I am proud to release. I gave it my best and I hope you enjoy it!

1. Open app
- Located in menu bar

2. Select monitor configuration
- Monitors are arranged based on their position relative to each other
- Selected monitors can be any configuration of 1, 2 and/or 3.

3. Click enable
- The overlay should now pop up

4. Use the slider to change the brightness level.

5. Enjoy!

What's New in Version 1.3

- Made monitor icons automatically rearrange to match desktop orientation
- Made screen remain dim while in expose (note: it is currently imposible to have the app remain active while in mission control. I spent the greater portion of a week trying to figure it out, but sadly it appears to be impossible with the standard apple libraries. Sorry to all who wanted that feature!)
- Fixed constraint error
- Removed misc files (decreased app size!)

NOTE: This feature is new, and as such may have issues. I have tested it to the best of my abilities, but if you encounter any bugs please email me ( Thanks!

I would like to briefly thank everybody who has downloaded the application, especially those who left reviews/emailed me! The fact that you took the time to write a nice little paragraph about something I made is incredibly gratifying. If you have any questions, comments, or requests please do not hesitate to email me ( Thanks!


Screenshot 1
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Customer Reviews

App works great but to be clear, it doesn’t adjust the brightness on the display...

The app works great, and from the user’s perspective, it appears to dim the monitor. In that I am grateful because I like dim displays at night in the dark. But one thing that needs to be pointed out is that it doesn’t change the brightness control on the attached display and therefore is not decreasing the power consumption of the attached display when dimmed. This app overlays an opaque black on the display and sets the opacity for some level in order to simulate a decrease in bghtness.

Hey, it works and my eyes are none the worse for wear because of it, but I have spent the better part of my career working on energy mangement issues and I am disappointed Apple and the display OEMs haven’t worked this problem out (the cinema displays need a USB cable to have the MBP control them...). It’s a simple problem for them to fix if they would work together.

Anyhow, to the app developer, good job and BTW, the display pyronometer (aka; ambient light sensor or auto brightness control sensor) in the MBP/imac/etc is available to developers. You should tie into it and adjust the brighness of displays automatically based on the observed brightness in the room. It’s trivial to get the sensor data and it’s an enum with kGetSensorReadingID as it’s first member, and the ints reflects a scale between dark and saturation. You could then dim displays based on ambient light conditions.

Works, but with some problems

This app works great and I have been using it for months now. Over time though, I have noticed some minor annoying issues. First, when I have this app set to start up with my mac the application does not work and I cannot enable or disable it. I then have to quit and relaunch the app for its functionality to return. Second, if I have one monitor plugged in with the app running, then I plug in an additional monitor the app doesn’t recognize it and I have to quit and relaunch the app. Final problem I have noticed is that when switching spaces the dim overlay flashes to regular brightness then back to the brightness that I have set. It creates an annoying brightness flicker. I have yet to try out any other brightness apps but this one could use some screen recognition fixes and startup fixes

Huge improvement

The 1.3 update is a huge improvement over the last version. Now that the mission control/exposé issue has been dealt with, this easily takes the top spot as far as screen dimming solutions go. Easy to control and with a great range of settings, and the multiple monitor support works just like it should.

Additionally, when I emailed the developer with my mission control complaint, I received some of the best support I've ever gotten. The dev has earned both my money and my respect.

Do yourself a favor and buy this thing already!

View in Mac App Store
  • $1.99
  • Category: Utilities
  • Updated: Jan 23, 2013
  • Version: 1.3
  • Size: 0.9 MB
  • Language: English
  • Seller: Atlas Wegman

Compatibility: OS X 10.6 or later, 64-bit processor

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