Black Watch tartan also has been the summer uniform since 1966 .
In 1936 , the winter uniform was changed to Black Watch tartan , after the then principal , Lavinia Clouston , had seen the uniform at the Presbyterian Ladies ' College , Sydney .
Black Watch   Black Watch also has been the Black Watch   since 1966 .
In 1936 , the winter uniform was changed to Black Watch tartan , after the then principal , Lavinia Clouston , had seen the uniform at the Presbyterian Ladies ' College , Sydney .