T hinges can also be done with rice paper and using methyl cellulose mixed with water as adhesive. I used to do that with watercolors, although in more recent times have retreated to the Lineco tapes. Rice paper for mounting can even be "cut" by drawing a wet line with a wetted watercolor brush and then gently pulling the paper apart. That leaves the edges as feathered and less likely to create bumps.
This is true, though I've preferred using whole wheat starch, home made, an epic adventure in the doing , because I just prefer it that way.
If I were making a carved woodcut blick or repairing a book, work on paper, it'll be wheat starch, every time otherwise, a lot of folks prefer Methyl Cellulose for its easy to find for sale, nature.
100% cotton rag watercolour papers are easier to part by water line, but I've found that creasing the desired water line, sharply defined, with a bone folder, Teflon or natural, allows a small hair brush loaded with water to limit the water to the now folded line.
Folding the crease line, back and forth several times will start the "pulling apart" of the cotton fibers, which when wetted, will part more easily.
One note on the major difference of Western papers and Japanese Washi, is that Western papers are mostly worked side to side, making a final product with a bias the paper with a definite 'smooth tear' direction, with one layer of fiber.
Quality Washi is actually a few or many layers lain one on top of another, ie, layer one, a side to side settling of the fibers on the paper screen of the shaking frame, then layer two is made by redipping the frame into the vat of loose fiber and shaking it forward and back to make a cross grain layer.
Layer three is a return to a side to side motion and layer four, forward and back.
This is repeated until a suitable thickness of paper is made for the type Washi being made.
This gives the Washi it's traditional strength and is a major reason it's preferred for book and document repairs as well as doll makers.
Washi comes from it's maker as a watermark, meaning if you drop some water on it, it will spread everywhere, where Western papers that are starched, will leave a drop of water beaded up on its service
It is more difficult to tear in a straight line but the creased water line will do the trick, when carefully made.
This contributes to its strength tin "T* hinges.
Most Western watercolour papers are internally starched, with the starch limiting the
absorption and travel of water.
Quality Washi, is generally not starched by the paper maker, awaiting the process being done by a contracted person, who will apply starch on the surface of the paper, with a broad, soft hair brush.
Washi starch also has a limited 'working lives, which it's up to a, Japanese style woodcut printmaker (most likely water based pigments) to work within.
Western watercolour papers can remained in usable starched condition for years, decades even.
Way too long, I know, but maybe of some use to others here.
Cheers