Museums, cylinders, and painting on silk

We went to the Asian Art Museum yesterday, which is always and all-day affair and usually exhausting. But we wanted to see the Cyrus Cylinder while it was here. It's a fascinating exhibit, both historically and artistically.

But also there was Japanese Art from the Larry Ellison Collection, and it got me thinking about wall scrolls. More specifically how many of them are painted on silk.

Now you can't really just paint right onto plain silk because it will bleed. Silk painting usually uses a resist of some kind but the wall scrolls don't look like they use that. I would assume the silk is treated in some way - like the way linen or cotton canvases are treated and gessoed - but my Google-fu is not turning up what I want to know. You can get silk already prepared for painting, but I can't find anything that says what is traditionally used. Or even not traditionally, I'd settle for a modern equivalent.

And then I found this artist who paints freehand on silk with sumi ink. But all it says is that she uses a fixing solution in the ink to make the garment washable.

And I'm sitting here going "What fixing solution? What do you use?? How do you prepare the fabric??? AAAAAAAAHH!!" But my Googling has turned up even less on this than on silk wall scrolls.

But goddamit I wanna know how she does that!!

(Also still want to know how wall scrolls are made.)