The Yuki-tsumugi technique is employed to produce pongee silk (also called raw silk) - a light and warm material with a characteristic stiffness and softness, traditionally used to make kimonos.

UNESCO: Culture

It's easy to see why the material spoke to the director: With his painterly filmmaking style, his characteristic interest in the intersection between longing and restraint, and his ongoing fascination with the early postwar England of his own childhood, Davies has been able to shape the stage play to his strengths, telling the story from Hester's point of view.

CNN: Review: 'The Deep Blue Sea' is nuanced

So what we want to do is fine-tune that special characteristic of the light so it shines back and it doesn't absorb into the material and cause damage.

NPR: Using Science to Rescue Art