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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

7 Answers 7

up vote 5 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 ( 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 '14 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 '14 at 8:10
@StevenLu I have a macbook pro and in the Ubuntu partition I indeed can set backlight brightness with much more control than on OS X. I have even made a small widget for that. Sad that for OS X things can't be so simple. – pepper_chico Nov 17 '14 at 5:10

I only know how to lower the brightness at its lowest by the way you already mentioned on your post and just like you, it's not enough. My alternative when I work late at night is an app called Candlelight and I fairly enjoy it! It's not a free app but it's just about $1 to help your eyesight on the long run!

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Discovered A better solution by modifying system kexts that doesnt rely on 3rdparty apps and actually lowers the actual lcd brightness levels,

DISCLAIMER modifying kexts has risks and can mess up your mac, I am not to be held responsible if your your OS breaks,

I used xcode to change the data for my lcd panel in AppleBacklight.kext/Contents/Info.plist In my macbook pro 13" 2011 the panel data is in IOKitPersonalities>AppleIntelPanelA>ApplePanels there is a string of hexadecimal values for each panel ID, eg my panel is 9cc5, which shows up as F10T9cc5 and the values are <00110000 00210029 00340042 00530069 008700ac 00d30103 013e0187 01e20252 02de038f>

the lowest brightness starts from the second pair of hex values (0021) in this example the second step is 0029 then 0034 and so forth, up to the max value of 0x38 (038f)

you can change that string to get a wider range of brightness e.g

<00110000 00100015 00250034 00490060 008000ac 00d30103 013e0187 01e20252 02de0710>

after setting the values fix permissions and rebuild cache (you can use terminal or Disk Utility to Fix permissions and DCPIManager to rebuild cache)

make sure to allow OSX load the modified (unsigned) kext by entering this in terminal

sudo nvram boot-args=kext-dev-mode=1

note the 0710 at the end of the data that is the maximum brightness allowed by my HD3000 meaning my color control can go much darker and brighter than stock, I also want to point out that the values are given above are not linear at all, im too lazy to work on the steps right now. but the idea is get your desired minimum and maximum values and enter the proper values in between if you want a smooth transistion .

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Nice that you discovered the existence of /System/Library/Extensions/AppleBacklight.kext/Contents/Info.plist! Instead of IOKitPersonalities/AppleIntelPanelA/ApplePanels/F10T9cc5 (and how did you know yours was 9cc5?), did you also try IOKitPersonalities/AppleIntelPanelA/IODisplayParameters/brightness/min? While max is set to 255, min is set to 40, which looks a lot like the problem we are trying to solve. – Matt Apr 7 at 19:21
According to kextstat, AppleBacklight.kext is not loaded, but AppleBacklightExpert.kext is loaded (and is being used by AppleMuxControl.kext). I'm confused -- how can AppleBacklight.kext have an effect when it is not loaded? – Matt Apr 7 at 19:29
funny thing is i stumbled across this when was having issues with a replacement lcd panel which had a very low range of brightness (it was too bright at the lowest value), you can find the display id using colorsync i tried the min and max values but they didnt work for me, – Dante the Metaphor Apr 8 at 1:52
System Preferences>display>color and click on "mmod" youll find your panel model id there (in my case 00009cc5) – Dante the Metaphor Apr 8 at 2:10

My recommendation is a hitherto-little known gem, called ScreenShade.

There are several decent Mac software screen dimmers out there, of which I've found the ones whose dimming method is to apply an increasingly opaque black 'overlay' over the screen to be the most superior in appearance (providing much higher quality 'low blacks' than Shades which does its dimming via color profile/gamma level tweaking) and in doing so, also playing nice with famous color temperature regulating app, f.lux.

The best examples in this group, are Shady (whose development has been abandoned by its dev and has a no better rogue clone in the Mac App Store), ScreenDimmer, Screen Shade, and Work at Night. (N.b. these last two, confusingly appear to be clones, by the same dev on the Mac App Store.)

But if you're looking to more fully emulate the Mac's in-built hardware dimming in software, you're looking for an app that can have the dimming triggered via hotkeys, system-wide.

Annoyingly, none of the just-listed quality 'overlay method' apps actually provide keyboard shortcuts (at present).

So for all the above criteria AND having keyboard shortcuts, the only one I have found is the humble Softonic-hosted ScreenShade, est. 2008!

ScreenShade for Mac

It's working on Yosemite 10.10 no problem, and has a decent little preferences window including even customisable support for multiple/secondary monitors! Its only drawback, is that the hotkeys' granularity in dimming up and down is a little less than one would ideally want (i.e. the jumps are fairly large), but this is a small concession given it at least provides hotkeys, and it does go down to very low levels (with fairly good clarity), all the same.

So until contenders like ScreenDimmer, Shady, or Screen Shade / Work at Night do anything about it, if you want something with hotkeys and simultaneous operation with f.lux (and to do it in software), this looks to be only app that can do it.

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I really like this solution because it works with my external monitors. It's the first one I've come across that does this. – haventchecked Jun 11 at 21:30

None of the apps got the screen totally black.

Neither id using the F1 Mac screen brightness.

But using BOTH DO!


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We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

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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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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