Costume designer Annamaria Heinreich tells the Salzburger Nachrichten why puffy shorts are out for Peter Stein's new Salzburg Don Carlo.
Stein has set his production at the time of the story, when Blackadder-style horsehair-stuffed bloomers were all the rage. Heinrich says these are unflattering and hard to wear on stage, so she looked at historical paintings for an alternative solution. In some Italian works she found narrow, pleated pants with a slim leg, cut above the knee. These are worn with a waist-length lapped doublet.
Historically accurate clothing would be uncomfortable and impractical, and the detailing too expensive. In any case, Heinrich's main consideration is to make the singers look and feel good.
So Kaufmann wears a simplified version, adapted for freedom of movement and breathing.
The pant solution in more detail: