Datacolor Spyder3 Elite Help Manual page 61

Select Gray Balanced Calibration
Help Index
Usual Setting
The usual choice for this option is 'on'.
The Purpose of This Step
This option allows the user to disable the gray balance algorithm used in calibration.
When calibrating certain displays, disabling gray balance may provide improved
results.
The Long Answer
By default, this option is always turned on for all displays.
For LCD displays this is usually the best choice in all cases.
CRT displays generally do not need additional gray balancing during calibration
therefore some users turn off this option for their CRTs to accelerate the calibration
process.
Our current experience with projectors shows mixed results. In many cases LCD
based projection devices work better with gray-balance turned on and DLP based
projectors work better with it off, but this may not be universal.
Further Information
For information such as a list of Frequently Asked Questions and details on all
Datacolor products be sure to visit our website: www.datacolor.com/Spyder3