DYEING PROCEDURE FOR NATURAL
FIBRES USING VEGETABLE DYES


Today the vegetable dyeing are only made by hand in particular geographic areas, where an old
tradition has been maintained (for example in Provence), which was till end of nineteenth
century the only known dyeing system. Today these dyes can be created using a dyeing technology, which permits to use these dyeing substances
inside a modern industrial production. In the following table we can compare the
natural dyeing materials and the synthetic dyeing stuffs.
NATURAL DYES
SYNTHETIC DYES


Raw materials originating from renewable agricultural sources. Synthetic
dyes from non –renewable sources. Extraction and purification technology
of the dyeing colours. These procedures are simple and produce a limited
environmental impact. The agricultural producers can work using these procedures by themselves
(Often they do simple decoctions of the macerated plants).

Sophisticated chemical synthesis production technologies and installations whose elevated costs can stand only big industries
(Basf, Hoechst, Ciba- Geigy etc.). Bad and difficult control of the environment problems caused by the colours production.
On the other hand by natural dyes is the toxicity really not relevant for operators or end-consumers.

The work place healthiness depends on the big chemical industries with big environment problems due to the
production realised in the East at lower costs ( the most important industrial chemical groups let producing in China and in India).

The majority of the synthesis dyes can present toxicity problems due to aromatic amines,
that cause cancer and are not allowed in Europe. That substances are largely used for
intermediate chemical reactions. Natural dyes mean no problems due to the exhalations and are completely biodegradable.

The exhalations due to the dyeing procedures at elevated temperatures
can be more or less poisonous depending on the dyeing substances.
The dyeing substances in the activated sludge installations are scarcely degradable.