Somebody at the Apple discussion board helped me out and solved the problem.
What happens is when you're running Photoshop, the computer switches to its Nvidia card instead of the built-in Intel graphics card, and for reason, this switch is not happening in my computer.
I installed, as advised, the useful app gfx card status (http://codykrieger.com/gfxCardStatus) that lets you select what card to use. This solved the problem immediately.
I'm having the same issue on my brand new MacBook Pro with Mountain Lion and Photoshop CS6. I downloaded the gfx card status app and it allows me to switch back and forth between the graphics cards, but I don't understand when the computer should be using one graphics card or the other.
Is there a reason my computer was automatically switching to the NVIDIA GeForce GT card? Is it okay to run Photoshop on the Intel HD Graphics 4000? Is there any way I can recalibrate the colors of the display when using either card to match?
Thanks for the help!
As I said in my post on the Apple board, my bluish tint problem when switching graphics cards eventually just went away - no idea why. And I tried recalibrating when I had the blue tint screen but do no avail.
I can open Photoshop and use it with my Intel integrated card sometimes - PS itself doesn't seem to make the switch automatically. But when I open Bridge (which I use almost always) the discrete graphics card kicks in. My temporary solution was to use gfxCardStatus on discrete all of the time. And after a while, when I began switching to integrated while on battery, my problem vanished.
But if you've a new MBP (mine's a late 2011 yet still under warranty until 2015) I'd take it back to the Apple Store and have them switch it out for another machine. The problem doesn't seem to crop up often (else there would be many more complaints) and it seems to be only on 2011 and 2012 machines. I don't think it's an Adobe problem at all as it happened to me when any app that uses discrete graphics would kick in (including Google Chrome).
I didn't send in a bug report to Apple because I thought that the problem was only with my machine. Yours is only the fourth time I've heard of the dreaded blue tint occurring. Take your machine back to the Apple Store and show them the problem. Maybe they will have a better fix than just using gfxCardStatus.
Photoshop is not supposed to switch cards - the OS is supposed to disable the integrated card and use the big GPU automatically.
It sounds like the OS is not making that switch correctly.
Further, there is some problem with the integrated GPU or it's driver that is causing a color cast. How it could affect all applications - I don't know, someone from Intel or Apple will need to debug that.
Fortunately, you can turn off automatic graphics switching and just use the pro GPU and not the integrated mini GPU.