Question: So I went and bought myself a brand-new indigo Iwata
hakama from a friend.
So far, I've soaked it in salt water for about four nights running to
try to set the dye. I wore the thing for the first time tonight and,
boy, are my dogi pants blue! Unfortunately, so are sections of our
mat. I went and tried getting the stuff our using peroxide and a
sponge but it's tough. Luckily, our mats aren't canvas -- they're
those vinyl faux tatami things. Anyone have any tips on getting this
stuff off the mats? I was at the dojo for about thirty minutes after
class scrubbing away -- after mopping the place, too. Any tips on
cleaning those blue streaks would be greatly appreciated.
Quick Answer: If it's bleeding, wash it! 2 or 3 or 4 times,
repeatedly, with soap such as Ivory Soap or Woolite. Using a
detergent like Tide may dissolve the indigo somewhat due to its
The longer answer involves chemistry and history.
The advice to set the dye with vinegar or salt is commonly heard and seems
to make sense from the standpoint that indigo is mildly soluble in a
reducing solution, insoluble in an oxidized state. But these approaches
cannot be an issue at the point that you have an actual bleeding hakama --
the acid of the vinegar does not glue the indigo to the fabric by making it
less soluble. Possibly the tradition of "vinegar to set the dye" is a
holdover from dying wool, a final rinse that would be better for the wool
than leaving it with any amount of alkaline soap residue.
Saltwater also has nothing to do with the chemistry of indigo dye.
Peroxide is essentially super-oxygenated water. It will certainly not
dissolve the indigo (but you might keep it insoluble and all in one place
so you can rip it off with sheer determination and muscle power). Will
soaking the hakama in a diluted peroxide solution help "set" the dye? You
might get more thoroughly oxidized indigo chunks but that will not help the
problem as the dye that is coming off of your hakama is not in the hakama
-- it is ON it. Think of the excess indigo as blue fuzzballs or chalk dust.
Something that does not blend with the fiber itself.
I suspect that many purveyors of "genuine, natural indigo-dyed" material
heap undissolved indigo onto the cloth just to give it a darker, richer
color much of which is illusion and falls off later. In real life, and with
a cotton hakama, it is far better to just wash the excess out before it
falls out in chunks all over your mat and furniture. But why is there
excess dye in the first place?
Modern methods of indigo dyeing involve a chemical reducing solution
which simply cannot get the dark dark blues that the older methods
did. (The thiourea dioxide chemical commonly used for reducing the
indigo to make it soluble in dyeing is commonly available as
"Spectralite" usually found next to the shoe polish and such in many
grocery or drugstores, in fabric or craft stores. Sodium hydrosulfite
may also be used and can be found commonly as "RIT Color Remover." If
youre trying to clean a mat be sure to test it on a small,
inconspicuous and low-stress side spot of the mat first to make sure
it doesn't take everything else off too. It will certainly be safe for
restoring your white cotton dogi pants.)
To dye with indigo in these modern times, you mix up a potfull of
thiourea dioxide or sodium hydrosulfite and water and add indigo
(natural or synthetic -- they both have the same chemical formula).
The result is a pale YELLOW GREEN solution known as WHITE indigo.
You dip the cloth in the dye, pull it out, and before your very eyes it
starts to change from green to blue. Why? Because the indigo is oxidizing
-- reacting with the oxygen in the air -- becoming insoluble. It's
delightful and magical to see.
In theory, you can dip it back in again for another coating of indigo
to make the color a little darker. This is fine a few times, but very
soon you have a problem. Enough thiourea dioxide or sodium
hydrosulfite in the solution to reduce the indigo not only keeps the
indigo in the dye-pot in solution, it also dissolves the indigo
already deposited on your cloth right back out again. Consequently,
you can never get the deep dark blues obtained through traditional
What were the traditional methods?
A reducing environment via bacteria in a pit of aged urine and its highly
fragrant biological byproducts. Very effective, but much slower -- and
An old dye book mentions a dyer who had switched to the new-fangled
synthetic indigo. Apparently customers would check for the authentic urine
aroma to be sure they were getting the real goods, so he included a recipe
using urea to provide the "authentic" smell.
However. . . at best, indigo is not very soluble. It tends to deposit on
the surface of the fiber which is why blue jeans (traditionally dyed with
indigo) weather and fade the way they do; the blue eventually wears away
leaving the white cotton thread showing through. If you've ever read the
epic "Musashi Miyamoto" you will remember that one of Otsu's odd jobs as
she follows Musashi about the countryside is pounding cloth with a mallet
to squoosh the indigo into the fiber.
The old method required weeks or months. Thiourea dioxide or sodium
hydrosulfite dye solutions take mere minutes but because of the
impossibility of obtaining dark blues with "Authentic Indigo" by
modern methods, there seems to be a temptation to make the cloth look
bluer than the chemistry actually allows. What to do? Simple!
Oxidize the solution in the dye-pot so it turns blue (i.e., creates blue
chalk dust) and pile these onto the cloth.
This is counterproductive per effective dyeing, but useful per economics if
you want a deeper blue but don't want to waste time and money doing it
right. The cloth APPEARS to be bluer thanks to a powdery coating of tiny
grains of oxidized indigo deposited ON the cloth. They will fall off with
wear, smurfing anything they touch.
Once again, the only cure is simply to wash the garment until the excess
dye is gone. If the resulting color is too pale blue for your taste, consider machine
dyeing with a RIT Indigo Blue. In either case, if you end up with a blue
washer, throw in a packet of RIT color remover and all will be well.