Apple AppleVision monitors (OS 7.1) - Manual (Page 37)

2 Open the Monitors & Sound control panel, then click the Color button.
3 Open the Ambient Light pop-up menu, then choose Custom.
The Ambient Light window appears.
4 Hold the ambient light tool against the screen and select the square that most closely
matches the color of the tool.
If you find a square that matches, click Save; then enter a name for this
setting.
37 Color Settings