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Monitor profile not sticking after sleep

Matt Suess

pro member
Ever since I upgraded to Leopard from Tiger I have been having a problem with my custom monitor profile not sticking. It will work for a couple days, then eventually when waking from sleep the main monitor (I use 2 monitors - main one is calibrated) wakes up at maybe 20% brightness - forcing me to re-calibrate. Cycle goes on every couple days or so.

I doubt it is an issue with the profile (using latest software) and guess that a monitor preference (or sleep preference, display setting preference) got screwed up during the upgrade. Any guesses as to which preferences I should trash to try to fix issue?

Thanks
 

nicolas claris

OPF Co-founder/Administrator
Hi Matt
Don't you have turned on a function to change automatically the brightness of monitor depending of ambient light?
 

nicolas claris

OPF Co-founder/Administrator
http://www.macfixit.com/article.php?story=20090512221023108

10.5.7 update: display, blue screen, and boot loop problems

Display Resolutions are Incorrect

Another prominent issue seems to be certain display resolutions are disappearing, resulting in the computer outputting non-native display resolutions to the monitor. In most cases, instead of being able to choose 1920x1200 as the resolution (the native resolution for many widescreen displays), the computer will only output 1920x1080 (the maximum for HDMI connections). This seems to be a conflict in the drivers, since 1920x1080 is the maximum display resolution for HDMI connections.
There may be several approaches to fixing this problem. The first would be to try a PRAM reset, which can be done by holding the options-command-P-R keys all at once at reboot, and holding them down until the computer resets a few times, then releasing them and allowing the computer to boot normally.
If a PRAM reset doesn't work, try a workaround suggested by Apple Discussion board user "cizko", which is to install a screen output tweaking program called "SwitchResX" for fine-customization of monitor outputs. The program is a demo, but installing it, setting the screen resolution, and then optionally uninstalling it seems to clear the resolution problem the OS X update.

A word of note: some people have found that in using SwitchResX, the only way they were able to get things to work was by going to the "Timing Parameters" settings and checking "Use Simplified settings", and then changing the drop-down menu from "GTF" to "CTV-RB".

Though this does not really describe your problem, zapping the PRAM can only be good…
 

Matt Suess

pro member
Thanks Nicolas - I will try that system preference - and will also reset the PRAM, though I thought resetting PRAM wasn't needed in the last few versions of OsX (haven't done that in ages).
 

nicolas claris

OPF Co-founder/Administrator
Thanks Nicolas - I will try that system preference - and will also reset the PRAM, though I thought resetting PRAM wasn't needed in the last few versions of OsX (haven't done that in ages).

Tell us if it solves your issue or if you have found another solution…
 

Matt Suess

pro member
I reset the PRAM, trashed that preference file, re-calibrated and now I wait. If all goes well for the next 4 days or so I will assume problem solved and report back. Thanks for the suggestions.
 

Doug Kerr

Well-known member
Hi, Matt,

Ever since I upgraded to Leopard from Tiger I have been having a problem with my custom monitor profile not sticking. It will work for a couple days, then eventually when waking from sleep the main monitor (I use 2 monitors - main one is calibrated) wakes up at maybe 20% brightness - forcing me to re-calibrate. Cycle goes on every couple days or so.

My guess is the problem is not the actual profile that is involved buy rather the "LUT load" - the table of settings loaded into the lookup tables (LUT) of the graphics card that gives the display an approximation of the desired color space (the "calibration" aspect of "calibration and profiling"). The profile then allows profile-aware applications to perfect the conformity. (The calibrating LUT load is actually stored in an "appendix" of the profile file itself, thus giving rise to the confusion between the two processes.)

I know that there is a similar problem with some Windows laptops in that evidently the LUT is reset to its "default" load when awakening from sleep or hibernation. One fix (rather agricultural) provided by Datacolor, the people who make the Spyder monitor calibrating and profiling systems, is a "forced LUT loader" that you can manually invoke from a desktop shortcut to force reloading of the LUT with the proper LUT load after awaking from sleep or hibernation. (I know that's pretty bogus, but until the actual problem can be solved, it's better than nothing!)

I realize that this is no help to your situation, but I thought you might be interested in the background.
 
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