displaymacbook proscreen
Is there a tweak, hack, or piece of software that can adjust the brightness of the MacBook Air's screen below the settings that MacOS X allows by default?
In low light the lowest brightness setting is too bright for me (and the setting after that is black so that doesn't work at all). 🙂
You would expect an app that dims the screen to save power. LEDs show a linear relationship for luminous intensity vs. forward current. The more you dim your LED display the less current it consumes.
(I'm assuming you have a LED-backlit display as all current-model MacBook Pros and Thunderbolt Displays are, and I looking at a LED data sheet found at SparkFun for the intensity/current relationship. It should be the same for any LED-based product.)
BUT if the app is not actually dimming - just covering everything with a transparent layer - then it may use more power. That app's reviews suggest it causes the discrete GPU to become active so I don't think there's any way it could be saving you power, more like the opposite. Adding a transparent layer over the entire display may decrease the apparent screen brightness but increase battery consumption due to the GPU having to do more work to blend the transparent dimming layer with other elements on the screen.
OS X Lion added per-user screen sharing: the ability to have multiple remote desktop sessions active on a single Mac at the same time. It's not a perfect solution, but you may find it good enough for your case.
When you connect to your Mac via Screen Sharing make sure the session is in Control Mode, not View Mode. You can switch modes by pressing Cmd+Option+X in the Screen Sharing app.
Once in Control Mode, look under the View menu and you should see an entry that says "Switch to Virtual Display". Select that to change the session to a virtual display, not the current desktop display, and log in as yourself.
The main display on your iMac should go to sleep according to your screen saver and energy settings once you've disconnected your remote session from the physical display and moved it to a virtual display.
The only flaw in this approach is I know of no way to start Screen Sharing on a virtual display from the get go. So the initial connect always wakes up the physical display.
Update for Mavericks
The "Switch to Virtual Display" option in the Screen Sharing app went away in Mavericks. Instead, upon connecting to the other Mac with Screen Sharing:
If someone else is already connected to the Mac as a remote user, a dialog asks if you want to share the display with the other remote user (Share Display), or log in concurrently using a different user name and screen (Log In). Choose the option you want.
If you choose Log In, you will share the Mac with the other remote user, but you won’t share the same screen.
Here's an example. In this case I tried to connect a Screen Sharing session from my iMac to my wife's MacBook Pro where she was already logged in. This is the dialog I get when trying to connect:
Best Answer
I use and recommend Shades (free), which can darken the screen beyond the built-in brightness control. If you really want to get it darker, use the built-in shortcut Cmd+Opt+Ctrl+8 to invert the screen colors (same command reverses the effect).
Nocturne (free) allows you to tweak some of the inversion settings.