There are two kinds of silk (1) raw silk (reeled silk, thrown silk,

drawn silk), and (2) waste silk or spun silk.

Raw silk is that directly taken from the cocoons. Waste silk is the

silk from cocoons that are damaged in some way so that they cannot be

reeled off direct. It is, therefore, carded and spun, like wool or


Silk in the raw state is covered with a silk gum which must be boil

off before dyeing is begun. It is tied up in canvas bags and boiled up

in a strong solution of soap for three or four hours until all the gum

is boiled off. If it is a yellow gum, the silk is wrought first in a

solution of soft soap at a temperature just below boiling point for

about an hour, then put into bags and boiled. After boiling, the soap

is well washed out.

Generally speaking, the affinity of silk for dyes is similar but

weaker in character to that of wool. The general method for dyeing is

the same as for wool, except, in most cases, lower temperatures are

used in the mordanting. In some cases, soaking in a cold concentrated

solution of the mordant is sufficient. The dyeing of some colours is

also at low temperature.