Unlike the vat dyes most other dyes are brought directely from a solution to the fibres. The quality of their fixation on the fibres depends very much on the type of fibres which we can simply divide into animal fibres (proteins), plant fibres (cellulose) and synthetic fibres like polyamides, polyesters etc.

For the following experiments two dye-baths are produced and three different materials are tried to dye in each bath:

Prepare strips of white cotton, wool and polyester.


Dye-bath 1:

Prepare a water bath: Take a 600-ml-beaker and add ca. 200 [ml] of tap water.
Warm with a BB to ca. 60 [°C] and check with a thermometer.
Weigh 0,5 [g] of crystal violet and dissolve it in 50 [ml] of tap water in a 400-ml-beaker. Warm in the water bath and add another 200 [ml] of water and ca. 2 [ml] of
50 % acetic acid.
Add the materials and allow to dye for at least one minute.
Afterwards the materials are washed thoroughly.


Dye-bath 2:

Weigh 0,4 [g] of Basilen Rot E-B and give it into a 600-ml-beaker. Add ca. 300 [ml] of tap water. Then add 15 [g] sodiumchloride and 1,5 [g] soda (sodiumcarbonate) and stir with a glass rod to dissolve the substances.
Finally ca. 1 [ml] of conc. NaOH (sodiumhydroxide, 33 %) are added.
Now the materials are put in the bath which should be heated to ca. 80 [°C] using the BB and a thermometer.
Allow to dye for ca. 20 minutes and wash thoroughly afterwards.


Observations? – Explanations?