DISCHARGING:
Discharging is the process of removing
dye
(by destroying or altering the dye "chromophores") with various
chemicals
or bleach, often in pleasing patterns or designs through
Shibori
or
Tie Dye methods, or by
stamping,
stenciling or block printing. Discharging can be incorporated into more
complex designs with over-dyeing other colors or combined with painting,
printing or stenciling with opaque Fabric Paints like
Lumiere, Neopaque
and
Setacolor.
Discharging can also be used to "fix" dyeing mistakes. Discharging is one
more way to make your own incredible unique fabrics for quilting or clothing.
Fabrics discharge with different chemicals depending on the type of fabric
and what it was dyed with. Some dyes won't discharge at all, or only with
very dangerous chemicals, which we don't want to carry because of safety
issues. Also, discharging rarely returns fabric to its original color or
white. Some blacks, for example, will only discharge to a nice reddish brown
color, while others will go to a very pale tan. The moral of the story is
test test test!
Work in well-ventilated areas, and use our new
Multi Gas/Vapor cartridges for the
Deluxe Dust Mask for added protection
as the discharging chemicals give off strong Ammonia fumes, or you have the
chlorine fumes with the bleach. We carry several books with good
information on discharging: Complex Cloth, Textile Dyeing, and Imagery on
Fabric.
Discharge paste
is a reducing agent. It is fairly safe to use, the main byproduct being
ammonia. It is for natural fibers and unlike bleach, it doesn't damage
them. It is safe for
silk!
It removes most fiber reactives (such as Dharma's Procion dye), direct dyes
and acid dyes. It is somewhat thick, so you can brush it on, screen it on,
stencil it on, etc. You let the fabric dry and steam it with a steam iron
or steam in a steamer for 10 minutes or so. You basically stop when it
stops discharging, then wash your fabric in a good detergent like
Synthrapol,
and rinse in
Milsoft to restore softness. It works well on stuff you dye
yourself with the above mentioned dyes, but does not work on the black rayon
fabric or garments or black cotton T-shirts we are currently selling because
they are dyed with dye that responds better to bleach.
Thiourea dioxide is also a reducing agent. It is used to remove most fiber
reactives (such as Dharma's Procion dye), as well as some direct dyes and
acid dyes. It is especially useful on cellulose fabrics, since it is used
in conjunction with
Soda Ash. It is sometimes used on silks or wool, but
one should always keep in mind that Soda Ash is harmful to those fibers, and
they should be neutralized with vinegar afterwards.
Immersion:
Thiourea dioxide is usually used as a discharge bath, for removing the
color from a whole piece. It is therefore sometimes very handy for
correcting dyeing "mistakes", or lightening a fabric for over-dyeing. A
dyed fabric can be tied into a pattern or design as in Tie Dye or Shibori,
then put in the discharge bath for interesting effects.
A typical recipe for 1 lb of fabric:
A non-reactive pan, like stainless steel or enamel (NOT aluminum, iron, etc)
2 Gallons of water
Add damp fabric to the above bath and heat to a simmer. While simmering,
add 1/4 additional tsp Color Remover every 15 min for a total of 1 hour.
Simmer for an additional 15 minutes. Frequent gentle stirring throughout
the process gives more even results, just as with dyeing. You can add
more color remover if necessary with no harmful effects. Remove, rinse,
and then wash your fabric in a good detergent like Synthrapol. You can
also use Milsoft in the final rinse to restore (and then some!) the
softness and drape of the fabric.
Also known as Spectralite, Color Remover is often used in conjunction with
Soda Ash for indigo dyeing.
Direct Application:
It can be used to make a homemade discharge paste as well for cellulose fibers:
1 tsp
Soda Ash (dissolve in a little hot water 1st)
1 cup water
combine the water and Alginate in a blender, or add the Alginate to the
water while stirring rapidly. Then stir in the Color Remover and the
dissolved Soda Ash. Let the mixture sit for at least 10-15 minutes to
thicken. Paint or print onto the fabric. Before it is quite dry, it
needs to be steamed 10-20 minutes, or it can be ironed with the steam on
until the desired results are achieved. Protect the iron and ironing board
with paper towels. Wash and rinse thoroughly as above.
DISCHARGING WITH BLEACH:
Above is an example of our
Black Rayon Fabric
discharged with 100% bleach. This is the fabric we make all our black rayon
clothing
* out of.
*NOTE about discharging rayon fabric:
Rayon is weaker when it is wet than when it is dry. We used full strength
bleach on some black rayon to discharge it and rinsed it immediately after
it discharged for a minute or two and both the discharged areas and the
untouched black areas ripped very easily in one direction when pulled.
After the fabric was dry it did not rip, even where bleached. Conclusion:
You have to treat wet rayon very carefully, and it is not the discharging
(if done properly) that is making the fabric weak. It is important to
support the whole garment if you are going to lift it out of a
dyebath when wet. Just grabbing part of it with a stick or other object
could cause it to rip.
Bleach is a strong oxidizing agent,
which is very hard on fabric (it really destroys protein, so use something
else on silk or wool!) and has to be used carefully! The advantage of
bleach is that it discharges a larger variety of dyes than the safer reducing
agents like Thiourea Dioxide and Discharge Paste. For best results bleach
should be diluted with water so it doesn't just burn right through your
fabric, then neutralized with
Bleach Stop to stop the action, as soon as the
desired or maximum results have been achieved. However, if testing proves
that only full strength bleach will work (like on our Rayon), just be extra
careful - keep an eye on the progress and as soon as you have acheived
desired results (should only take a few minutes!) rinse an neutralize the
bleach immediatly!
Immersion:
Bleach solutions for a discharge bath or spray can range in strength from
2 TBS per cup water (1:8) to full strength bleach. You often have to test
each different fabric with different strengths - the ideal goal is to use
as weak a solution as you can to get the desired results. Start testing
with a weak solution and work your way up to a stronger one if necessary.
Heat helps the process, so the warmer the water, the quicker the reaction.
Remember to rinse as soon as it looks like the action has stopped or you
have acheived your desired results, then neutralized with Bleach Stop
(directions below) to stop the action of the bleach so your fabric won't
be damaged. Then rinse and wash thoroughly as below.
Use 1 oz per gallon of warm water
Agitate for 15 minutes
Rinse and wash your fabric in a good detergent like Synthrapol, and you
can also use Milsoft in the final rinse to restore (and then some!) the
softness and drape of the fabric.
Direct Application:
Bleach and water can also be combined with a thickener to make a
discharging paste, which can be painted, stenciled, stamped, etc., onto
your fabric. You can use the old standby, sodium alginate to thicken it,
or our new
Bleach Thickener, which stays stable longer in the presence of
bleach (24-36 hours!). Some books have recommended a product called
Monogum, which breaks down (turns too liquid) even faster than the above
mentioned thickeners.
The Bleach Thickener is designed to be used with bleach and water to produce
a thickened paste which can be applied to fabric in order to remove color.
The paste can be painted or printed onto the fabric. The thickener remains
stable in bleach for 24 to 36 hours. The bleach thickener is for use on
cellulose fibers such as cotton, linen, and rayon. Not recommended for
protein fibers such as wool and silk.
For a Screen or Block Printing Solution:
1/8 cup bleach (TEST!! – it depends on how strong you need the bleach to be for a particular piece of fabric)
For painting it on:
1/16 to 1/8 cup bleach (TEST!! – it depends on how strong you need the bleach to be for a particular piece of fabric)
Following the percentages above add bleach thickener to the bleach until
mixture is a smooth, thick and even consistency.
Paint or print this mixture onto fabric which has been previously dyed.
The longer that the mixture is left on the fabric and the
thicker the application of the bleach paste, the more dye that will be
removed. However do not leave on for longer then several hours as the bleach
may weaken the fabric. Once dry or discharged "to taste, wash fabric to
remove thickener. You can use the Bleach Stop above to neutralize the bleach.
If mixture is too thick, or you want a slower, or less of a reaction, you
can add some water.
When using the bleach thickener on dyed fabrics you will find various
results depending on the type of dye and color that is chosen for the
background. We recommend our Procion MX dyes for cellulose fibers. Many
dyes will not discharge to a white but rather to a lighter version of the
same color and sometimes to another color entirely. Some colors and dye
types will not discharge at all or very little. Results may vary. A little
experimenting is required.
If using Sodium Alginate:
1 qt water
~4-8 tsp
Sodium Alginate (experiment with the thickness until it meets
your needs)-use HV unless drawing fine lines with an applicator.
Put the water in a blender, ideally, and sprinkle the alginate in slowly
while the blender is going. Allow to set for 2 hours or so to continue
thickening.
Use this thickened water to dilute your bleach, substituting it for the
Bleach Thickener above. It will go bad somewhat quicker, ie. turn liquidy,
so only make as much as you will use fairly quickly. The thickened water by
itself will store nicely in the refrigerator for a few weeks - just give it
a clear non-food label!
With both of the above thickened bleach methods, after you have painted,
stenciled, printed or screened the mixture on, let sit 5-10 minutes or until
the desired amount of color is removed. Then rinse thoroughly in warm water
and soak in your Bleach Stop solution as above. Next wash in Synthrapol,
then you can use Milsoft in the final rinse to restore softness.
