There are two kinds of natural dyes: substantive and
adjective. SUBSTANTIVE dyes (lichens and walnut hulls, for instance)
need no mordants to help them adhere to the fiber. ADJECTIVE dyes do.
The mordant joins with the fiber and the dye to set the color permanently.
It enters deeply into the fiber, and when the dye is added, they combine
to form a color; since the mordant is thoroughly embedded, so is the
color. This is the principle behind the process. Adjective dyestuffs
are not able to penetrate the wool enough to keep from washing or fading
away—unless a mordant is used.
Keep mordants out of reach of kids, animals and weird adults. Mordants
are not all poisonous, but why risk trouble? Store them safely away
when they aren't in use. Don't breathe in the fumes while you are mordanting.
NEVER use the same pots for cooking and dyeing.
GENERAL RULES FOR MORDANTING
All recipes here are for one pound of wool. Wool is the easiest
to dye; cotton and linen are possible too, but the process will be more
complicated and the results may be less pleasing and/or permanent. Halve
or double mordant amounts to prepare half or twice as much wool. Use
a non-reactive pot—enamel (unchipped) or stainless steel. Brass, copper
or iron pots will do their own mordanting, providing special effects
you may not care for.
Wool is more easily dyed as fleece or as yarn wound
in skeins. In either form it must be clean (commercial yarn usually
already is); dirt will repel the mordant and later on the dye. Tie skeins
(tight knot, loose loop) in four places to prevent tangles. If the loop
is too snug, you will have tie-dyed yarn. It is possible to dye wool
as fabric, but hard to do it evenly.
Soak wool for several hours, to ensure even take-up.
NEVER put dry fiber into a mordant- or dye-pot unless you want streaks.
Fill a large enough pot with enough water to not crowd the fiber. Add
the mordant and dissolve completely, stirring with a clean stick or
glass rod. Bring the bath to room temperature and add the wet wool.
Bring to a simmer and hold there for an hour. DO NOT
BOIL. Stir occasionally VERY SLOWLY & GENTLY. (HEAT and AGITATION
Remove pot from heat and let cool—preferably over night.
Remove wool from pot. It is ready to be dyed or it may be stored wet
or dry, for later dyeing. Some people think mordanted wool will take
dye better after it has sat for a while. Wet wool has been stored successfully
for up to six weeks. Ventilate it and turn it to prevent mold. If you
store your mordanted wool dry, be sure to soak it well before dyeing.
Please see our "Natural Dyeing" instructions
for further information.
ALUM (potassium aluminum sulfate) is the most common
mordant. If you are not sure what you want to do, mordant with alum,
and use the others as additives. Alum does not effect color. It is usually
used with cream of tartar, which helps evenness and brightens slightly.
Three ounces of alum and one of cream of tartar is a good start; if
you have heavy wool, use four ounces of alum. Too much alum makes wool
sticky. Alum mordanted wool stores well, wet or dry.
IRON (ferrous sulfate) is called copperas. It will
sadden or darken colors, bringing out green shades. Usually wool is
dyed BEFORE mordanting with iron. Simmer dye-bath for ½ hour,
remove wool, and add ½ ounce of iron and one ounce of cream of
tartar to pot. Dissolve thoroughly then re-enter wool. Simmer ½
hour more. Rinse well (remember to cool slowly-see above); too much
iron will harden wool and make it streak.
TIN (stannous chloride) blooms or brightens colors,
especially reds, oranges and yellows. Almost always used with cream
of tartar — ½ ounce tin and 1-2 ounces of cream of tartar for
a pound of wool. Simmer for an hour and rinse in soapy water before
dyeing. Tin is a good additive mordant. Store wool wet or dry. Too much
tin makes wool brittle. It is caustic, be sure to handle carefully and
clean up thoroughly.
BLUE VITRIOL (copper sulfate) saddens colors and brings
out greens. It is a good additive. Used alone, one ounce will mordant
a pound of wool. Rinse fiber well, store wet or dry. Blue vitriol is
TANNIC ACID is a good mordant if you want tans or browns,
or for cotton or linen (vegetable fibers). One ounce per pound of wool,
simmer for an hour. Wool mordanted with tannic acid before dyeing tends
to darken with age.
GLAUBER'S SALTS are a leveling agent, not a mordant.
Add ½ cup to your dye-bath to prevent streaking. Color will change
slightly. Wool dyed to slightly different shades with the same dyestuff
can be brought to a more even color with Glauber's salts. Add one cup
of Glauber's salts to your dye-bath, dissolve, add soaked wool and simmer
for ½ to one hour, until the different shades have blended into
uniformity. The final color will be a little duller.