The MacBook Pro Retina has 2 graphics cards, sort of. There is the integrated Intel 4000 "card" and the NVIDIA card (1gb VRAM). By default, dynamic graphic card switching is enabled in System Preferences, Energy Saver. After installing the application "gfxCardStatus" one can see which card is being used. If you have dynamic switching active the card used is dependent on which applications have been launched. For example, if Photoshop or Bridge is launched then the card will switch from Integrated to Discrete (NVIDIA). That raises the question: Is the profile generated by calibration software valid for both cards? I would not think so. This raises the question of how this is managed. I would always want the screen to be set up for imaging apps like Photoshop. Add in the variable of an external monitor and it could get complex. Any ideas? Barry Rudick