Fifteen double skeins. Fifteen double skeins or 30 small skeins are bound into a larger bundle called a book. But it is still not strong enough to be woven into anything except the sheerest material. It is strengthened by a series of processes called throwing. Throwing is increasing the twist or adding strands and twisting then together.
Workers boil the silk in a solution of that soap to remove the sericin.
The sericin can be removed either before or after weaving, depending on the type of fabric. This type of dyeing is called skein dyeing. Some silk fabrics are dyed after they are woven. This process is called piece dyeing. Automatic power looms have replaced hand-weaving methods in almost all countries.