A needlessly detailed breakdown of the visual language used in The East Palace
(Other parts: Framing, Framing (bonus), Colour, Light & Shadow, Camera Angles & Sound, Bonus)
As someone with a strong interest in historical fashion, I am always interested in the costuming used to give life to the characters. They tell their own tales, which are often highly specific to the culture they represent. While my other posts about framing, (lighting) colour, and light & shadow are somewhat universal for visual media, I don't pretend to know anything about the symbolism of certain colours or styles in Korean culture. What you'll find below is my interpretation and what I could find, but feel free to correct me if I'm wrong :)
Gu-cheon's progression through the show in terms of costuming is pretty straightforward and clear. The clothing he wears (in public) shows his rising status: from the dirty beggar clothes at the temple, to the strict black robes of the feng shui master and ending the show wearing a hat usually reserved for the upper yangban classes. A real social climber!
However, the clothing that reflects his "true" emotions is what he wears in private, and to some degree also what he wears in the realm of Gwi. It's looser, sometimes untied, flowy and comfortable. Deep down, GC still identifies as and feels most comfortable in the clothes of a temple orphan.
Saeng-gang's wardrobe is less straightforward, but infinitely more interesting as it reflects her standing and alliances within the court. For the entire first half of the show, she is wearing the uniform of a court lady (essentially a servant). She has been summoned to the court by her father, but is to keep her real identity a secret. It's only after confronting the dowager queen, and thus revealing who she truly is, that she starts wearing clothing that fits her station as a princess. instead of the shorter blue jacket, she now wears the longer jackets of a high-class lady, and a braid that falls down her neck instead of tied up on her head.
However, SG remains visually separate from the royal family. She is wearing finer clothing, but usually in softer pastels, not the colours or styles worn by the other members of the royal family. Only after getting possessed by the crown prince's spirit, does she become visually part of the family. As she wears the royal reds, she is not only part of the cursed blood, but she also shows her alliance with the royal family.
After being betrayed by her grandmother and learning the truth of the curse, SG visually departs from the royal family and returns to her pastels, though with elements of black added to her wardrobe this time.
Similarly to GC, the king's clothing differs greatly between his public appearance and his private clothing. In public, he wears the stately and constrictive red robes of his station, while in private he mostly wears looser black and white or pastel clothing. During the appeasement ritual, he wears the most ornate clothing with a headdress reserved only for specific rituals.
As the realm of Gwi is a twisted mirror of the real world, it makes sense that clothing colours are also inverted and changed. GC's blue and black robes turn blood red in Gwi, except for in the primordial gwi-mae's realm. His hairtie remains red though, which I would like to think is a wink to SG's red hair ribbon but may just be a coincidence.
SG's clothes also change between the two worlds. Her blue collar becomes bright yellow, her red hair ribbon turns black. In the final scene, her previously pink jacket becomes blood-red.
I love it when a character's wardrobe reflects their inner journey, and I would love to see all the choices behind the styling of our main characters. I wish I knew more about the meaning of colours in Korean clothing, because I feel like there's a lot more symbolism hidden there than I managed to pick up