This technique can be best understood if you imagine a combination of origami and dyeing. Although this method creates geometric pattern, the pattern looks quite organic with soft edges and rich coloring. And once you get hang of it, you realize there are endless possibility in the variations of patterns.
Itajime method can be used for both cold and hot dye bath(depending on the dye you want to use). I used sumi ink and indigo dye on silk fabric. Sumi ink could be omitted if you want to use indigo dye only: simply skip Step#2 below.If you want to use either cotton or linen instead of silk, you may need to boil the fabric to remove glue and wax from the fabric before you dye. And soy milk needs to be applied onto cotton (or linen) as mordant before you dye it with sumi ink.
Supplies needed:Indigo dye bath (I used pre-reduced indigo crystals, available at dharmatrading.com) Sumi ink (available in art supply stores and online stores)silk crepe fabric (please make sure it’s pure silk)pair of wooden triangle (these can be handmade or can be purchased online by searching “itajime wooden pieces”)rubber bands or a small clamp iron, pair of rubber gloves or disposable latex gloves, and timer or clock.
Choice of fabric: I recommend you avoid choosing blended fabric. This means you want to go with 100% silk. If you choose blended fabric, speckling effect will most likely occur. Additionally, for best result, you may want to choose a fabric that has not been bleached. Some fabric has optical brightener or bleach on it for a whiter look. Choosing fabric with least waxy whiteness and with more off-white natural coloring will provide the best condition for dyeing.
Indigo dye bath: You can find a lot of information about preparing indigo dye bath online. Pre-reduced indigo crystal is relatively easy indigo dye to use. It is chemically same as natural indigo dye reduced into crystal form (think freeze dry instant coffee). I personally choose to use this form of indigo because I do not have to use other chemicals when preparing the indigo bath. Unless you have an access to naturally fermented indigo dye stuff, using "pre reduced indigo" is more eco friendly and practical. If you opt to use botanical & organic indigo, indigo will need to be fermented over a few days. With organic indigo dye stuff, fermentation process can be expedited with additional chemicals. These chemicals are usually toxic, which defeats the purpose of choosing organic indigo over pre reduced indigo crystals.
I recommend using indigo crystals to prepare the bath without any other chemicals. I like to use warm to hot water to make the indigo bath. You want to make sure dye bath is well stirred and all the crystals melted in the water. It is best if you prepare the indigo bath about 1 hour before you start dyeing. You want to avoid oxidation of the bath by preparing the bath too early.
Step 1:Using hot water and PH neutral detergent, presoak and wash & rinse the silk fabric. This will remove any surface dirt or oil/wax which can prevent dyes to penetrating the fabric.
Step 2: prepare sumi ink bath by mixing 2 parts sumi ink and 1 part water. This ratio can be adjusted depending the desired darkness of gray. Submerge silk fabric and move it around to make sure all the surface of silk is coated. Squeeze out the excess dye, rinse and hang dry. This dye bath can be used again for a week or so – make sure you keep it in a cool place.
Japanese Sumi ink is made from plant soot. It can used as dye on silk without any mordant.
Step 4: Presoak the bundle in water for 10 to 30 minutes, making sure water penetrated into the bundle thoroughly.
Step 5: Take the bundle out of the water bath, gently squeeze the bundle to the point where it isn’t dripping wet. Immediately submerge the bundle in indigo bath.
Step 6: Once bundle is in the bath, you want to make sure it is fully submerged in the dye and it stays under. Gently massage the submerged bundle, making sure indigo gets into all the exposed parts of the fabric.
Step 7: After one minute in dye bath, take the bundle out and gently squeeze the excess dye. While bundle is outside the indigo bath, you want to gently massage and carefully open folds (only on exposed area of bundle, do not open the bundle yet). This is to introduce oxygen onto the surface of the fabric. The oxidation of the indigo is what makes the indigo turn blue and to stick to the fabric – so this is an important part of the dyeing. Once all exposed area is carefully opened, leave the bundle at a well ventilated area, preferable in natural daylight. Leave the bundle out at least for 3 minutes or longer. Submerge the bundle again for 1 minute, take out, massage. Let it rest for 3 minutes. You can repeat this process 3 to 10 times depending on desired intensity of the indigo. I dipped my fabric five times to get medium-light shade of indigo.
Step 8: After the final dip, transfer the bundle into water bath. Gently rinse in running water for 30 seconds to a minute. Take the bundle out, squeeze out water gently, let it drip dry until dripping stops. Open and unfurl the fabric. Let the fabric hang dry(preferably in natural light).
Step 9: Wait at least 24 hours then wash the fabric in cool water with gentle detergent. If you are hand washing the fabric, avoid soaking, rubbing or wringing the silk. Use gentle cycle if you use washing machine. I like to use splash of white vinegar in final rinse to get all the soap out of silk. This step will also help to restore subtle luster of silk.
The combination of sumi ink with indigo produces subdued indigo navy color with visual depth. This combination was used in traditional Japanese textile to achieve navy blue, which was considered more “genteel” shade of indigo since plain indigo garments were often worn by farmers and other working classes. Although this dyeing method was mostly used on cotton and linen, I used it on silk. Crinkled texture of crepe silk adds to the richness surface.
Pattern and color will always vary. Sometimes you may get something quite different than what you have intended. But if you consider the result reflects the sum dyer's work, dye bath, fabric, the environment in which dyeing was done, you can delve more into the mysteries of working with nature.