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When working late, I'd like to lower the screen brightness further than the OS X allows in using the brightness keys.

While you can use ++F1/F21 to change the brightness in smaller quaterish increments, this does not have an effect between 0 and 1 bars.

i.e. The values 0.25, 0.50, 0.75, 1.00 have the same brightness. The brightness only incrementally increases for quaters above 1.

In Ubuntu I've accomplished very low brightness settings by manually changing integers in the configuration files. Is there something similar that I could do in OS X?

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1 - This works for the volume the same way.

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As I lower my brightness, the irritating humming sound gets louder. If i could get it lower than the bottom setting, I'm sure the sound would send me insane ;) –  stuffe Jun 26 '12 at 20:56
@stuffle I don't hear any sound from the display, only from the keyboard. When using very low brightness settings in Ubuntu, I did not hear anything either. –  gentmatt Jun 26 '12 at 20:58
I think it's a known fault on my iMac 24... –  stuffe Jun 26 '12 at 20:59
Oh, well that explains everything! :D –  gentmatt Jun 26 '12 at 21:00
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3 Answers

up vote 3 down vote accepted

Another application for decreasing brightness is Shady. But like Shades, it just draws an overlay over the screen and doesn't actually turn down the backlight.

LCDs require a similar amount of energy to display bright and dark pixels, and some LCDs actually require slightly more energy to display dark pixels, so Shady and Shades might even increase energy use.

There is a small Objective-C utility (https://github.com/serverhorror/brightness/blob/master/brightness.c) for changing the brightness of displays, but it cannot set the brightess below the normal minimum value either.

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This look promising! The overlay does not seem to affect the colors as bad as shades. But, I'll have to try it again tonight. –  gentmatt Jun 27 '12 at 4:41
Here's something interesting about Shady -- it doesn't affect the brightness of the cursor. Not sure how I feel about that, but it definitely emphasizes the fact that it is simply using a brightness overlay. I really wish I could further decrease the power consumption by somehow hacking in and decreasing the actual minimum display brightness further... –  Steven Lu Apr 2 at 8:09
@gentmatt You say in Ubuntu you can get it even lower. Can you tell if it is actually getting the backlight to be even dimmer and drawing even less power? Is this with a MacBook? Which one? Maybe we just need a kernel extension for OSX to achieve it. –  Steven Lu Apr 2 at 8:10
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Check out the app called Shades:

About Shades Shades is a FREE utility for controlling the brightness of your screen. It runs in the background providing always-available fine-grained control over the brightness of your display via a slick Mac-like interface

Though all modern Apple laptops have brightness controls for dimming the screen in dark conditions, there are several situations where the built in controls are unsatisfactory. The granularity of control is rather coarse, and the minimum brightness setting still quite bright when working in pitch darkness. Perhaps you need to use your machine in a darkroom, or like to work late at night without disturbing your partner who sleeps beside you? Perhaps you need to dim the screen on a desktop machine, and the display you are using offers no such facility? If this is the case for you, then try Shades.

Note: Shades may interfere with colour calibration software, and should not be used if colour accuracy is critical.

My iMac has a "fault" in that the lower I set the brightness, the noisier the screen buzzes, due to an issue with the capacitor that does the work. But using this app I can get the brightness down way further than using hardware controls on the backlight, and the buzzing is not introduced either. Double result!

It's also useful to use this tool for altering the brightness on external displays which do not respond to the brightness key controls.

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Thanks, this is a very convenient to use solution. It's not perfect, because it seems to change gamma values or something like that (cold colors). However, this will be fine in most cases. –  gentmatt Jun 26 '12 at 21:14
There are a few apps that do similar, but this one plays nice without a dock icon etc. Yes, it's just overlaying the screen in essence to give the illusion of dimmer, but it is effective if you don't mind the colours looking a little odd if you take it right down low. –  stuffe Jun 26 '12 at 21:18
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If you are doing a lot of typing, and not working with photos or videos, etc you could always use the color reversal trick. Just press control+option+⌘+8, and all the colors on the screen will be totally reversed. No more white screen; black instead. Much easier on the eyes.

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