How long can I wash the silk scarves painted by Shuituo?

Water extension painting, pinyin for shuǐtàhuà, refers to filling a container with water, and then adding the prepared pigment into the water according to the painter's idea to make it flow naturally in the water, and forming a pattern or corresponding texture according to the painter's idea and painting requirements. When painting, according to the requirements of the picture, lightly spread paper such as rice paper or cardboard on the water surface to make full use of the absorbency of the paper.