I have a few questions about calibrating a 30" Apple Cinema Display.
1) Is it necessary to let the ACD warm up for an hour without using the Screen Saver function in Mac OS X?
As long as the screen saver is displaying an image, you should be fine.
The point of letting the display "warm up" is that the backlight needs to be stable for reliable profiling.
2) Should the ACD's Brightness setting be set to Maximum in the OS X Displays System Preference before I calibrate using my calibrating software and puck?
No, that is not necessary. Your calibration and profiling software will give you instructions depending on your desired target brightness.
4) I'm also not sure about the Luminance / contrast ratio settings. I guess from the fairly opaque instructions I should just choose Maximum for each of the various pull down menu choices. For example, for White and black luminance choose the defaults which are the Maximum radio buttons? I don't believe the Optix will allow me to correctly measure an external light source. Correct? Should I change these settings to 120 cd/m2 for White luminance? What should be the choice for Black luminance?
Ideally, black should be black, i.e. 0 cd/m^2, although it's unlikely your monitor will achieve that perfectly (the backlights must switch off, or no light must penetrate the LCD).
Selecting luminance is something you'll find varied opinions on. Remember that what you probably want to achieve, is predictability in quality between what you see on your screen in soft proofing mode and what you get on your prints. This depends on your ambient lighting as well as the light you use to view your (dry) prints.
Contrast should be left in a neutral state in your monitor, the only thing you should adjust during calibration is brightness; leave the rest to the software.
If I recall correctly, there is a pretty decent tutorial or essay on the topic right here on the LL, but I'm not able to find it, sorry.
