Quantum Data 802BT - Manual (Page 560)

550 Appendix A Command Reference
TOBL
set levels relative TO BLanking
Class Custom image primitive
Description Temporarily changes how the signal levels are determined for a given color intensity level.
The default method uses black as the 0% reference level and peak video as the 100%
level. Inserting TOBL moves the 0% reference point to the blanking (blacker than black)
pedestal level. The reference point remains shifted only for as long as the image is
displayed.
Command syntax TOBL