Silk has been with us for a long time. Records indicate that silk has been in production before 6803 BC. Silk is archival. There are examples of still brightly colored silk found in China from the third and fourth century BC. Silk was alsothe painting support of choice long before canvas or paper was ever used.
Protecting Fine Art Silk Paintings
Dirt - When the silk painting is steamed, the dyes are bound in the fiber. The painting is hand washable using a mild soap and can be ironed with high heat.
Light - more specifically, UV light can fade the colors in a textile. The best way to protect a silk painting is to keep it out of direct sunlight. Framing the artwork under UV-protected glass such as museum glass can eliminate the impact of fading.
Moisture - silk resists mildew and most other bacteria and fungi. Moisture and humidity can make the silk fiber brittle over time. So it is especially critical, if framing under glass, to make sure that there is air flow around the painting to reduce the possibility of moisture build up.
Reference - You can find more information on the history or biochemistry of silk and silk painting in the book "Silk" by Mary Schoeser, Yale University Press, 2007