I don't know why, but sometimes or always (!) I have noticed that whenever I run an application with admin privileges on Windows 7, brightness automatically increases.
Is it with everybody? If it is even with a few, what is the reason for this?
It's possibly an illusion from the screen going 'darker' during the prompt to run as an administrator.
Your eyes quickly adjust to that brief change in brightness so when it switches to it's normal brightness it 'appears' brighter. Like when on a bright day and some clouds come over and you are briefly in shadow and then when the cloud lifts a second or two later it seems much brighter.