If you use two or more color monitors connected to one computer, all of the monitors must be the same model from the same manufacturer (for example, Eizo CG247W) and from a single production run.
The monitors should have been in use (turned on) for an equal number of hours.
When calibrating multiple monitors, Matchprint Virtual will automatically position the calibration window on the second monitor after successful calibration of the first monitor. For luminance, it is important to use a value that can be achieved by both monitors. When first putting the monitors in service, perform a calibration to maximum and record the achieved values for reference. It is still recommended that you set luminance to a fixed value of 200 or 10% below the maximum luminance and in the case of multiple monitors, the lowest maximum luminance of the multiple monitors should be used when factoring this value.
For more information about Mac computers, see the Apple Web site at http://www.apple.com/. For more information about monitors, see the vendor's Web site.