The Truth About CRT (a.k.a., Black Level Ain't Everything) (1 Viewer)

[ChrisWiggles]

Many things can affect convergence drift, and ISF calibration, per se, won't have any real effect on convergence drift. A good ISFer may align things better, and do other more advanced tweaks, which will minimize drive the electronic corrections less, which will help minimize drift. What you are displaying shouldn't affect convergence.