Pages: [1]   Go Down

Author Topic: MBP changes brightness by itself  (Read 4637 times)

dchew

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1020
    • Dave Chew Photography
MBP changes brightness by itself
« on: November 14, 2009, 07:03:00 am »

I'm fairly new to macs so I’m hoping there is some setting I’ve got wrong that will solve this. I'm trying to figure out why my mbp changes it's brightness setting even though I have the "automatically adjust brightness as ambient light changes" unchecked.  It tends to get brighter, i.e. the Brightness slider moves up from where it is in this screen shot to somewhere above the word “ambient.” Boy I wish that brightness slider had a box where you could type in the percent.  Then I could just retype in the calibrated setting I like since it is between the F1/F2 presets.

[attachment=17916:Screen_s...01.55_AM.png]

The Energy Saver settings are as follows:
[attachment=17917:Screen_s...18.57_AM.png]
I understand that it dims itself when on battery, but that’s not the problem I’m having (I uncheck that box if I’m editing photos on battery).  There is some combination of operating on battery / putting to sleep / waking up on power that give’s my mbp a mind of its own and resets this.

It’s not that it is too hard to change back, just that I often don’t realize it happens and my editing goes screwy.

Anyone know why the mbp does this and if there is a way to stop it?

Dave

17” mbp unibody w/matte screen; OS 10.6.2
Logged

Jonathan Wienke

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 5829
    • http://visual-vacations.com/
MBP changes brightness by itself
« Reply #1 on: November 14, 2009, 07:34:34 am »

Look in your power management settings, there should be separate settings for battery and AC power. Whenever you switch, these settings override the current setting.
Logged

dchew

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1020
    • Dave Chew Photography
MBP changes brightness by itself
« Reply #2 on: November 15, 2009, 12:00:10 pm »

Quote from: Jonathan Wienke
Look in your power management settings, there should be separate settings for battery and AC power. Whenever you switch, these settings override the current setting.
Jonathan,
The battery power settings are indeed different in that the "slightly dim display..." and the Automatically reduce brightness..." checkboxes are enabled.  However, these settings both dim the display; I seem to have the opposite problem.  It actually gets brighter, i.e. the slider setting goes up.  These settings are in "Energy Saver."  Is there some other place I need to look?

Dave
Logged

Ken Bennett

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1797
    • http://www.kenbennettphoto.com
MBP changes brightness by itself
« Reply #3 on: November 15, 2009, 06:03:13 pm »

In System Preferences, click Displays, and UNcheck "Automatically adjust brightness as ambient light changes."
Logged
Equipment: a camera and some lenses. https://www.instagram.com/wakeforestphoto/

Jack Flesher

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2592
    • www.getdpi.com
MBP changes brightness by itself
« Reply #4 on: November 15, 2009, 06:32:52 pm »

Do you have your function keys set as regular function keys or special function keys?  As special, an F2 key press adjusts brightness higher if you inadvertently tap it.

If that's not the issue, another one is that your MBP will reset to default Power Management brightness at re-boot.  It should not do this unless you want it to, and to clear the behavior you can to do a Prom Reset --- hold the P and R keys down as you boot, holding them until you hear the SECOND ding, then release.  All your settings should be reset now, though sometimes you need to repeat this process twice to have it take.  Now set brightness to desired level and restart, and make sure your original settings stuck through the restart.

Cheers,
« Last Edit: November 15, 2009, 06:33:55 pm by Jack Flesher »
Logged
Jack
[url=http://forum.getdpi.com/forum/

dchew

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1020
    • Dave Chew Photography
MBP changes brightness by itself
« Reply #5 on: November 16, 2009, 07:21:58 am »

Quote from: k bennett
In System Preferences, click Displays, and UNcheck "Automatically adjust brightness as ambient light changes."
Yes; the screen shots above show that I have it unchecked.


Quote from: Jack Flesher
Do you have your function keys set as regular function keys or special function keys?  As special, an F2 key press adjusts brightness higher if you inadvertently tap it.

If that's not the issue, another one is that your MBP will reset to default Power Management brightness at re-boot.  It should not do this unless you want it to, and to clear the behavior you can to do a Prom Reset --- hold the P and R keys down as you boot, holding them until you hear the SECOND ding, then release.  All your settings should be reset now, though sometimes you need to repeat this process twice to have it take.  Now set brightness to desired level and restart, and make sure your original settings stuck through the restart.

Cheers,
Jack,

The function keys are 'special,' so I suppose it's possible I'm hitting the key, but I would think I would notice the screen get brighter if I did that.  It seems to do it when it boots, like in your reset default scenario.  I'll check that.  Thank you.

Dave
Logged

CBarrett

  • Guest
MBP changes brightness by itself
« Reply #6 on: November 25, 2009, 10:30:01 pm »

Quote from: dchew
Yes; the screen shots above show that I have it unchecked.



Jack,

The function keys are 'special,' so I suppose it's possible I'm hitting the key, but I would think I would notice the screen get brighter if I did that.  It seems to do it when it boots, like in your reset default scenario.  I'll check that.  Thank you.

Dave

Man this drives me nuts!  My MBP does it too!  Not only that, it will occasionally drop out of the calibrated profile and I have to go back into the display pref tab to reset it.  This is my 6th Mac Laptop and I've never seen this before.  I just know that calibrated brightness is 4 squares down and I double check the brightness level pretty often.
Logged

Jack Flesher

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2592
    • www.getdpi.com
MBP changes brightness by itself
« Reply #7 on: November 26, 2009, 02:55:20 pm »

Quote from: CBarrett
Man this drives me nuts!  My MBP does it too!  Not only that, it will occasionally drop out of the calibrated profile and I have to go back into the display pref tab to reset it.  This is my 6th Mac Laptop and I've never seen this before.  I just know that calibrated brightness is 4 squares down and I double check the brightness level pretty often.

Defintiely try the PROM reset I detailed above...  It solved the same issues for me with mine.
Logged
Jack
[url=http://forum.getdpi.com/forum/
Pages: [1]   Go Up