Spectroscopic studies of weakly populated proton i13/2 bands in superdeformed Tl nuclei (around mass 190) and in the normally deformed, very light 183Tl nucleus are discussed. Among the results presented, the first measurement of a superdeformed quadrupole moment in an odd-Z nucleus, 191Tl, is reported. The experiments were conducted with the Gammasphere array as "stand-alone" device and coupled with the Argonne Fragment Mass Analyzer
