[Spliff]

My new iMac has the annoying habit of dimming its screen after being idle for a few minutes. I don't want it to do this. I hate having to move the mouse to un-dim the screen.

I tried unchecking the Energy Saver option "Automatically reduce brightness of the display before display sleep." As far as I can tell, enabling/disabling this option changes nothing. The screen dimming behaviour remains the same.

Does the iMac G5 have a built-in screen dimming function that can't be changed or disabled?

[iREZ]

i believe it's built into Tiger and not your iMac. you're pretty much stuck with this until apple decides otherwise, i know i get this on my powerbook, and only till i upgraded to tiger.

[Jerommeke]

I have given a bug report about this issue too. This strange phenomenon has been happing since the time when I had the option 'Automatically reduce brightness of the display before display sleep' on. Though I turned it off, it still reduces the brightness.

One of the many Bugs™ in Mac OS X Tiger, I guess.

[seanc]

Set the screen sleep to never. It dims a few minutes before the screen is about to sleep. Try doing the same for putting the computer to sleep as well.

[chenyichung]

go to "system preferences"
click on "energy saver"
click on "options"
uncheck "automatically reduce the brightness of the display before display sleeps"

[Spliff]

Originally Posted by chenyichung

go to "system preferences"
click on "energy saver"
click on "options"
uncheck "automatically reduce the brightness of the display before display sleeps"

Like I said above, toggling this option has no effect on the screen dimming. The option is a placebo. It does nothing. It must be broken. I'll file a bug report with Apple. Is sending "feedback" sufficient or is there a way to send a more detailed bug report?

[chenyichung]

works for me

[tomdeallycat]

Running 10.4.2 on AL Powerbook 15" 1.33GHz and I have the same problem. Just did a Google search because I was getting annoyed and found this thread. Maybe if enough of us file bug reports Apple will fix it.

[maCCer]

Originally Posted by Spliff

Like I said above, toggling this option has no effect on the screen dimming. The option is a placebo. It does nothing. It must be broken. I'll file a bug report with Apple. Is sending "feedback" sufficient or is there a way to send a more detailed bug report?

It works for me

[Jerommeke]

This does not work. What worked around my problem is setting the display sleep time to 15 minutes instead of 5 minutes, this also increases the time before it dims. It looks like there is a group of people who are able to reproduce this, and a bigger group who has no problems.

Would be nice if it could be figured out which settings (or hardware?) cause this to happen?

[cleanup]

Why disable it? The dimming feature is nice.

[sweetymac]

My imac always dims...when I first got it that never occured. But after I got it back from repairs it is always dim i mean right when I turn it on it is bright then it all of a sudden goes dim....but it does it right away. I can see everything fine on the screen, but its just not as bright. I wouldnt care if it did that only before it sleeps but it does it always.

[Jerommeke]

Everybody got its own taste of what is fine and what is nice, luckily !

[cleanup]

Originally Posted by sweetymac

My imac always dims...when I first got it that never occured. But after I got it back from repairs it is always dim i mean right when I turn it on it is bright then it all of a sudden goes dim....but it does it right away. I can see everything fine on the screen, but its just not as bright. I wouldnt care if it did that only before it sleeps but it does it always.

That sounds like a real problem.

....

That's all I have to say.

[Will C]

Juts a possible suggstion here, (though I don't have TIger or an iMac)

Have you tried trashing your powermanagement preference file? - this often fixes similar problems in Panther.

[andreas_g4]

Originally Posted by chenyichung

works for me

Nice to hear that. Smart post.

[Spliff]

Originally Posted by Will C

Juts a possible suggstion here, (though I don't have TIger or an iMac)

Have you tried trashing your powermanagement preference file? - this often fixes similar problems in Panther.

Yeah, tried that. Didn't work.

Another irritating thing is that the screen will dim while I'm watching a movie. That is so stupid. The OS should know that a movie is playing and therefore not dim the screen.

[cleanup]

Originally Posted by Spliff

Yeah, tried that. Didn't work.

Another irritating thing is that the screen will dim while I'm watching a movie. That is so stupid. The OS should know that a movie is playing and therefore not dim the screen.

Mine does, when I'm playing a movie in VLC, QuickTime, or DVD Player, it never dims or goes to screen saver, or sleeps. It also never sleeps when it sees that I'm downloading something.

[as2]

Originally Posted by cleanup

Mine does, when I'm playing a movie in VLC, QuickTime, or DVD Player, it never dims or goes to screen saver, or sleeps. It also never sleeps when it sees that I'm downloading something.

I've been having the same dimming problem, but also the screen saver comes on while i'm watching EyeTV...

[Crawdad]

I googled to this thread, found no solution, and then scrutinized my system files to discovered the foloowing solution. It seems to have stopped the screen dimming for me, when on external power.

Edit /Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist with Property List Editor or a text editor. In the dict under <key>AC Power</key> add a new key-value pair:


<key>ReduceBrightness</key>
<integer>0</integer>


No space between Reduce and Brightness! (Unlike some other keys you'll find in that file.) When I saved the file, the effect was immediate.

If your acccount doesn't have admin privilege (as it shouldn't!), make a copy elsewhere, edit the copy, use "diff -c ..." to make sure you got just the changes you wanted, then use sudo to move it to the right place. When I did this, the effect seemed to be immediate. YMWPV because you'll do some little thing differently. That's why you got a mac in the firs place!

[rafisaar]

Originally Posted by Crawdad

Edit /Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist with Property List Editor or a text editor. In the dict under <key>AC Power</key> add a new key-value pair:


<key>ReduceBrightness</key>
<integer>0</integer>


No space between Reduce and Brightness! (Unlike some other keys you'll find in that file.) When I saved the file, the effect was immediate.

I have this problem where my iMac G5 screen dims after a few minutes of use and never returns to full brightness until I reboot.
I performed the workaround above, but it didn't work. Also, nothing happened immediately after I edited and saved the file. However, I might have added the two lines to the wrong place.

First of all, <key>AC Power</key> appears twice: once under <key>ActivePowerProfiles</key> nd once again under <key>Custom Profile</key>. So where should these lines be added?

Also, if it's under the ActivePowerProfiles, should it be added immediately under the "AC Power" line or under the <integer>-1</integer> line?

And if it's under the Custome Profile then again should it come directly under the "AC Power" line or should it be put in the long list of key value pairs below?


Thanks,
Rafi

[natural1]

sweetymac:

If your screen dims immediately after turning your system on, it may be because it is loading a Colorsync Display profile that has reduced luminocity. Check out the Color tab of the Display System Preference and recalibrate your monitor to a brighter setting. Maybe this will help for this scenario?