What does my computer need in order to calibrate two or more displays?
Before answering this question, it is helpful to know a little about how calibration profiles function. Display calibration systems like Spyder5 create ICC profiles. An ICC profile for a display is made up of two parts: one part that works with color managed applications and the other works with the graphics card. The part of the profile that works with the application is a white point correction. The other part corrects the gamma and linearizes the values for red, green and blue by making an adjustment to the “Look Up Table” of the graphics card; otherwise known as the LUT. The adjustment to the LUT alters the signal to the display from the computer.
In order to calibrate multiple displays, your computer’s graphics card needs to have multiple LUT’s. Generally speaking, if your computer has a display connection then it has a LUT for the connection. Some entry level graphics cards may have connections for multiple displays, but don’t have a LUT for each connection. In this case, calibration is only possible for the displays that have corresponding LUT’s.