Display keeps changing and now....

I use an imac and several times I've come in to find the brightness is set to lowest setting. Now on this mac osx I do not have a automatic setting to select or de-select it kind of does it on it's own. Today was one of those days I went to display to make the change and when I did this the screen resolution was low making the screen appear huge! Anyone have insight to why this is happening?

OSX version? Model of iMac and what is "this mac" that you referred to in the second sentence. There is a brightness sensor in a lot of Macs that will adjust brightness to fit the background surroundings. You didn't say what you did to make the change you referred to. So tell us what you did, exactly, and maybe someone can help.

More info

Sorry new to this. My Mac is a all in one desk top model osx 10.5.8 Question why does the screen go dark now and then? This is something that I have not noticed in the past, I looked to see if my system has the feature like the mac books to just disable it but it does not. (system preferences, display) Now when I go into the the preferences to adjust brightness the screen the comes up with huge letters and a setting of 800 x 600 (stretched) and I have to reset it to 1680 x 1050 any ideas why? Thanks

OK, I'm running Lion, but let's see if this works. >System Preferences>Displays, uncheck the "automatically adjust brightness" box and make sure that the highest resolution available in the box on the left is highlighted. Go ahead and close system preferences. Now it should be at the highest resolution (small font) and the dimming should be disabled.

Can anybody with his version of OSX verify that set of instructions? I don't think Lion changed that, but I don't have SL anywhere to look.

EDIT: I found something else for you to look at. System Preferences>Energy Saver> uncheck the "Automatically reduce brightness before display goes to sleep and check how long the "Display Sleep" slider is set to wait.

EDIT: I found something else for you to look at. System Preferences>Energy Saver> uncheck the "Automatically reduce brightness before display goes to sleep and check how long the "Display Sleep" slider is set to wait.

Click to expand...

Was just gonna suggest that one....