The difference in color is due chiefly to the process of “retting.”
The fiber is separated from the plant by retting, beating, etc.
When the retting is complete, the flax is set up in sheaves to dry.
This loss is greater the finer the stems, and the longer the retting.
Then the flax is bound in bundles for the next process, which is retting.
Most of this richness is in the seed and the part of the stalk that is removed in the retting.
After the first few days of immersion the stalks are examined daily to test the progress of the retting.
It is stated that the colour of the fibre is darkened if the leaves are allowed to remain on during the process of retting.
The fibre is separated from the stalks by a process of retting similar to that for flax and hemp.
Any simple operation which improves the colour of the fibre or shortens the operation of retting is worthy of consideration.