discharge dye; print workshop notes.

 colour discharge (black silk) - clear discharge (black silk)

Discharge
The discharge technique makes it possible to put a white or coloured image onto a dark background.
A relatively simple technique that incorporates a reducing (bleaching) agent in the print paste.
The paste is printed, dried, steamed and washed. During the fixing (steaming) process the print paste bleaches out the dyed ground colour and replaces it with a white or cream colour. This mixture is known as white or clear discharge paste.
If coloured images are required an illuminating coloured discharge paste must be used. As with the white discharge paste, during the fixing (steaming) process the dyed ground colour is bleached out and replaced with the colour of the illuminating discharge paste.
Before printing the base cloth has to be dyed in an appropriate dischargeable dye. This will determine the success of the discharge print.
All dyes are dischargeable to a certain degree, while some dyes bleach out to a white, others, blues for example will change to a grey, turquoise or purple once steamed. Experimentation is needed to check for dischargeability.
White or illuminating pastes can be applied to the fabric in a variety of ways. The most common is screen printing, but block, stencil, mono and hand painting techniques are equally as good.
When using illuminating dyes for coloured discharge the basic principles of dyeing have to be taken into account, i.e. whether the dyes are suitable to the fibres of the cloth and observing that the correct fixing agents and processes are used.

Illuminating colour discharge dyes for silk wool and polyamide

Direct sky blue GD, yellow LFF
Acid yellow, red, violet, blue and black
Procion blues
Basic pink, yellow, blue, turquoise, flavine, orange
And most pigment dyes.
All of the Kemtex illuminating acid dye range - 13 colours

Illuminating colour discharge dyes for cellulose ( cotton, viscose, rayon & linen )

Most pigment dyes.
The pigment dyes produce crisp and brilliant colours and give the most consistent results from a relatively simple process.

Discharge is an exciting technique where fantastic finishes can be achieved. However it is a technique which is terribly inconsistent due to the following reasons.
-The strength, age, percentage and choice of reducing (bleaching) agent used.
-The type of printing auxiliaries and thickeners required.
-The length of time the discharge paste has been left before steaming.
-The humidity and condition of the steam.
-The type of dye used as the ground colour.
-The type of dye used as the illuminating colour discharge paste.
-The fabric used.

These inconsistencies more often than not enhances the overall finish of the cloth.
For consistent results experimentation must be carried out taking all of the above factors into consideration.
Good results are achieved when the paste is made, printed and steamed on the same day.

CLEAR DISCHARGE

400 ml WATER
35 - 25 gm MANUTEX F POWDER
1 tbsp GLYCEROL
100 ml BOILING WATER
50 gm FORMOSUL POWDER
Put 400 ml of water into the liquidiser, switch on and slowly add the 25 gm of manutex f powder to make a nice even thickener.
In a separate container mix together 100 ml boiling water, 1 tbsp of glycerol and 50 gm of formosul powder.
Add this mixture to the thickener and liquidise a few times until a lovely syrupy paste is made.
Leave to stand for 30 minutes
Apply the paste to a fabric dyed in a dischargeable dye. Better results are achieved when the paste penetrates the fibres of the cloth so it soaks through to the back of the fabric.
The print can dry naturally or it can be gently dried. Once dry, the fabric is steamed for 10 - 30 minutes for clean crisp colours.
Alternatively the discharge technique will work by ironing the print with the iron on its hottest setting. However this is a smelly experience and not really recommended. This method can also give the colours a brown tinge.
To wash out, run the fabric under the cold tap until the water runs clear. Then wash with a little detergent in luke warm water, making sure all the discharge paste is removed.
Finally rinse in cold water and dry.

DECROLINE DISCHARGE


100 gm SOLVITOSE POWDER
500 ml WATER
100 - 150 gm DECROLIN
50 gm GLYCEROL
200 ml WATER

Liquidise 100 gm of solvitose with 500 ml water.
Mix Glycerol and DECROLIN together to form a paste.
Add 200 ml water to paste and dissolve Decrolin.
Hand mix the paste into the solvitose mixture, then whiz a few times in the liquidiser.
This is an excellent strong paste, ideal as a white discharge paste but it can be to harsh as a base for illuminating colour discharge dyes.