This talchum performer displays the colorful silk hanbok, or "Korean clothes," worn by all of the masked actors. This type of hanbok is modeled on those from the late Joseon Dynasty (1392-1910). Even today, ordinary Korean people wear this type of clothing for special occasions such as weddings, first birthdays, the Lunar New Year (Seolnal), and the Harvest Festival (Chuseok).
The dramatic, flowing white sleeves help to make the actor's movements more expressive (useful when wearing a fixed-jaw mask).
This style of sleeves is seen in the costumes for several other types of formal or court dance in Korea, as well. Since talchum is considered an informal, folk performance style, the long sleeves originally may have been a satirical detail.