Lachlan,
If I understand your comments above about the pleating correctly, you are saying that, in addition to different styles of pleating (ie. mil box pleat used by A&SH vs. knife pleats used by BW), they also varied the color/lines that they pleated to? Can you explain more? In other words...If I were looking to pleat Black Watch Tartan in the style of the Black Watch (pre-amalgamation), what element of the tartan would be visible and what colors and lines would "flash" with the swinging of the pleats?