Winding consists of wrapping silver wire of an appropriate gauge around a gut core, for bowed string instruments, or silk for Romantic guitar.
During the winding, the core is held in traction by a weight that roughly reproduces the tension of the string on the instrument, as shown by the period illustrations, and this to ensure that the silver turns do not open for the expansion of the gut or silk core being tuned.
For the silk core, first choice material is used for its softness and resistance, and the sound quality obtained, in addition to reproducing the original one, is better than that of the strings of other manufacturers, who use nylon while offering their own products as "historical" (to check if it is nylon just burn it and you get the classic blackish "ball", while the silk chars producing an odor of burnt hair).