While changing the FL3 filter may reduce the problem, it does not eliminate
it since it still ignores the fact that there is signal in FL3 due to
the fluor being detected in FL1 (FITC). The only accurate solution is
to compensate from FL1->FL2, FL2->FL3 and FL1->FL3 simultaneously.
If hardware does not allow this to be done during acquisition, it can
always be done in software.
Bob Murphy
murphy@a.cfr.cmu.edu