I visited another website that says they only use shoufu-nori glues, not chemical-based ones, so that the scrolls age better. Can you inform me what glues your mounters in Beijing use?
That's kind of a tricky question. The traditional glues (like the Japanese one you mentioned, which I think may be based on a seaweed extract). I know more about traditional Chinese materials, but the Japanese materials are usually derived from Chinese ones.
In the completely traditional style, the whole wall scroll is pressed flat and temporarily adhered to a board. Layers of paste, paper, more paste, artwork, and silk are added. Eventually, the whole thing is peeled away from the board, and hardware such as the top frame and roller are added. This method uses a so-called natural paste. However, if you ate a bunch of that paste, it would still be toxic (natural does not mean non-toxic).
The result is very traditional, but this type of wall scroll mounting often develops wrinkles. Some also claim that it allows mold to grow more easily on the artwork.
We use a combination traditional techniques and materials along with some modern elements such as heat-activated adhesives, and double-sided tapes to build our wall scrolls. This allows us to offer a balance of high-quality traditional xuan paper and silks mounted using superior modern adhesives.
There are actually three general ways wall scrolls are made these days:
1. The completely traditional way, which may be more wrinkled or wavy, and costs twice as much in labor.
2. The balanced approach of using traditional and modern materials, with the wall scrolls being made by hand.
3. Very cheap machine-mounted wall scrolls which use all modern materials and almost no hand-work at all.