Pressure Resist Dyeing (itajime)

Itajime is a Japanese method of creating patterns in dyeing, somewhat similar to tie-dye. But instead of using string or thread to compress the fabric in places to prevent the dye liquor from penetrating, solid objects called resists are clamped onto it. The fabric is first folded repeatedly, resulting in bold geometric patterns.

Because the fabric is folded several times and in both directions, this technique works best with fine fabrics such as lightweight silk (eg habotai, pongé or crêpe de Chine) or cotton lawn. The finer the fabric, the more folds you can make and the more detailed the design can be. Natural fibres generally take a crease better, which is helpful, and are easier to dye than synthetics.

You’re going to have to do the dyeing in a bucket or on the hob/stove, because throwing a clamped bundle of cloth into the washing machine isn’t a good idea. The clamps may damage the drum and, even if they don’t, they’re likely to become dislodged by the washing action. You can’t use a microwave either, because of the need to use strong, metal clamps.

This technique works well with indigo or woad dyeing because the dyebath doesn't need to be heated and the fabric doesn’t spend long in it, so the wooden resists don’t get chance to become sodden and warp. You could use Kool-Aid to dye silk, as that is a quick process. If the dyeing method you are using takes a long time then it would be better to use a stiff plastic material for the resists instead of plywood. Perspex/plexiglass, HDPE or nylon should be suitable, depending on the dyeing temperature – for example, Perspex softens at about 80°C. You could use something inexpensive such as a kitchen chopping board, simmering a piece of it in a pan for an hour before using it, to check that it remains stiff.

Another issue arising from the use of steel G-clamps is their potential to affect the dye colour. Natural dyes in particular can be dulled by metal contamination in the dyebath, so a swift process has advantages for this reason too. Stainless steel G-clamps would be perfect, if such things exist. Traditionally, the resists are bound together with cord or string in itajime, but it’s hard to get the bindings tight enough and to keep them clear of the fabric so they don't produce a tie-dye effect.

I have a 3 month Pro membership to give away to the first person to post an "I made it!" comment with a photo of their finished itajime project.

Materials

• A length of plain white fabric or a pre-hemmed scarf, preferably cotton lawn or lightweight silk
• Commercial dye to suit your fabric – or you could use natural dye
• A dye vessel and utensils suitable for the dye
• An offcut of timber batten or plywood (preferably marine), not too rough-faced and thick enough to be really stiff
• Two woodworking G-clamps
• A saw
• Sandpaper
• Paper and pencil
• An iron

Start by washing the fabric to remove any finish that has been applied to it during manufacturing and deal with shrinkage. While it’s drying, have a look at the next step and work out what your design will be. This is also a good time to give your G-clamps a wash in hot soapy water to get rid of any dirt and grease. Rinse them well and dry them off. You can lubricate them again later when you go back to using them for woodwork.

When the fabric is still very slightly damp, lay it on a table and check that it's straight. If it looks more like a parallelogram than the rectangle it should be, stretch it across the shorter diagonal to even it up – get someone to help if necessary. You can then iron it to dry it and hopefully set it – cotton, linen and silk are best ironed slightly damp anyway.

Pull a thread at each end of the fabric to find the straight grain and then trim it to get a clean edge. Check that it is now an undistorted rectangle – you should be able to make further small adjustments using a steam iron on cotton or linen, but steaming silk is best avoided. If you plan to make a scarf or sarong from your dyed fabric then it’s a good idea to hem it now, before dyeing. That way the design will go right to the edges and not be cut off.

Fold the fabric in half lengthways, then in half again lengthways, and keep doing that until it is either about 10-15cm (4-6”) wide or it’s too thick and stiff to fold any more. Undo at least one fold if it’s very thick, because you’ll need to be able to fold it in the other direction as well when you come to prepare it for dyeing. Count the number of folds.

Then unfold the fabric and re-fold it in the other direction until you end up with a folded width that is roughly the same width as you got before. Make the final fold into thirds rather than in half if you like. Count the number of folds in this direction too. Make a note of these numbers, and also make a note of the height and width of the final bundle of folded cloth – this is the “tile” size. For example, to dye the 45cm x 130cm (18” x 51”) silk scarf in the first photo I folded it twice lengthways (ie into a quarter of its width), followed by twice widthways and then again into thirds (ie into 1/12 of its length), to end up with a bundle that measured about 11cm x 11cm square.

By the way, itajime is used in Japan for dyeing entire kimonos, and there are special ways of folding them that you can probably find with an internet search. So you could try folding a T-shirt instead of a plain length of fabric.

The design is created by the size and shape of the resists, how they are placed on the bundle of fabric, and how the fabric is folded. (More sophisticated itajime uses textured resists, but let’s not run before we can walk.) To start with, aim for no more than 4 or 5 "in half" folds (= dividing it into sixteenths or 32ths) across the shorter direction of your rectangle of fabric, and just 2 or 3 folds is fine for a narrow scarf. In the other direction you can create a balanced design by folding as many times as is necessary for each “tile” to be approximately square, or fold a different number of times for rectangular tiles.

You’re going to be folding the fabric repeatedly, first in one direction and then the other, to make a small rectangular bundle that is clamped between two resists. The more of the bundle area that is covered by the resists, the greater the amount of white in the finished pattern. The simplest designs use rectangular resists which extend beyond the edges of the bundle, although there’s no reason why you can’t use smaller ones, or circles, ovals, diamonds or any other shape. They are used in pairs, one on each side of the bundle.

Note that the folds will be in alternate directions, concertina-style, not repeatedly folding in half as you did to work out the tile size. This is because repeatedly folding in half takes more and more fabric into the fold zone with the result that the finished pattern will be distorted, whereas concertina pleating involves folding only a single layer at a time.

In the previous step you worked out the size of a smallish bundle that you could get out of your fabric. You might want to use a double-sized or even quadruple-sized bundle (ie one or two fewer folds) if you want a big, bold design instead of a smaller one with more repeating elements. So using my example of an 11cm x 11cm bundle, I could instead have gone for one that was 11cm x 16.5cm by making the last fold into two rather than into thirds, or even 11cm x 22cm by omitting the final fold altogether.

Now decide what size your resists need to be. Assuming you are going with plain vanilla rectangular ones, they should be at least a couple of inches (5cm) longer than the longer bundle dimension, but too long is better than too short because they need to overhang the edges of the tile. They should be about ¼ to 2/3 as wide as they are long, depending on how much white, undyed fabric you want to end up with. (Have a look at the two actual examples of dyed fabric in the first step and the computer-generated illustrations in the next one.) I used resists that measured 5cm x 18cm (2" x 7") for my 11cm x 11cm bundle.

When you've decided on a size, go to the next step before coming back here, because you may yet change your mind.

Cut a matching pair of resists from timber batten or plywood. The larger they are, the stiffer they need to be, so cut 4 and use them double if necessary.

Smooth and slightly chamfer the cut edges with sandpaper so they won’t catch on the fabric. Check that at least one face of each piece is smooth too, this is the face that will be towards the fabric.

If you can't be bothered with all of this, then you could use objects that you already have as resists. Melamine coasters, plastic or wooden rulers, ceramic tile offcuts, lengths of wooden batten and acrylic patchwork templates would all do, but bear in mind that they may end up dyed.

Half the fun of any resist dyeing technique is that you never know quite what you'll end up with, so you could just fold your fabric any which way and clamp on the resists randomly. Alternatively, take a piece of paper and work out a design.

Trim a sheet of paper to make its aspect ratio (width:height) approximately the same as the fabric you are going to dye. Then fold it lengthways in half repeatedly, the same number of times as you plan to do with the fabric. Open it out and fold it in half the other way, again the same number of times as you plan to do. Crease each fold well. Open the paper out and you will have a grid of small rectangular tiles, each in proportion to the bundle of folded fabric.

Cut a template from a piece of card to represent the resist. It should be to scale. With a pencil or crayon, draw around it on a corner tile and shade the space outside it. You could start by placing this virtual resist at an angle across the centre of the rectangle. Draw in horizontal guidelines with a pencil and ruler to indicate where the top and bottom of the resist will be on each tile.

Treat the first vertical fold as a mirror and draw in the outline of the resist on the next tile. Continue until at least 4 tiles have been drawn on across the width, then repeat with the next row of tiles by “reflecting” the virtual resist in the first horizontal fold. Shade in the areas outside of the resist to represent the dyed zone.

Starting at a different corner, see how the pattern changes as you vary the width and angle of the resist and/or move it down the tile. When the lower edge of the resist runs from the bottom corner of the tile, a diamond pattern emerges. Experiment with paper, or a graphics package, to find the arrangement you like best.

The blue and white image above shows a square folded in half three times in each direction (ie into 64ths), with the first tile outlined in red in each case. Subtle changes in the width of the resist, and the angle at which it is placed across the bundle, produce dramatic variations in the finished design.

You may decide your resists need to be a little slimmer, or wider, than you first thought to get the effect you’re looking for.

Iron your fabric again to make it perfectly smooth, then fold it long edge to long edge, right sides together. Crease the fold line carefully with the iron, keeping the long edges exactly together as you do. Precision is key here.

Since the fabric will be folded concertina-style, you need to think about whether each successive fold should be a “valley” or a “mountain” – they must alternate across the fabric. The first photo of this step shows valley and mountain folds in a sheet of paper.

When you open out the fabric after ironing in the first crease, right side uppermost, you’ll have a valley fold down the middle. The fabric is now divided in two with a crease at the ½ position. If you intend to divide in two only once more (ie into quarters overall), then the next two folds at the ¼ positions need to be mountain folds, in which case lay the fabric right side down and fold each long edge in turn to the centre crease, ironing along the new folds without removing the centre crease. However, if you are dividing the fabric into eighths across the width, then the folds at the ¼ positions should be valleys, so lay the fabric right side up when you make them. Then, when you come to make the 1/8 folds, you’ll need to turn the fabric over before doing so, first folding in each edge to the nearer ¼ line crease, then each edge to the ¼ line crease on the other side. The easiest way to get this right, especially if you are making 1/16 or even 1/32 folds, is to concertina-pleat a sheet of paper first and just make sure that the creases you are ironing into the fabric match those in the paper.

The bundle is made by folding the fabric concertina-like, starting at one long edge and working across to the other one, using the ironed-in creases as a guide. It's important to be accurate, placing the first long edge precisely on the first crease, then folding the fabric back on itself along that crease and so on. You may need someone to help you if you are working on a large piece of fabric.

Once you have it all folded in one direction, you then need to iron in creases in the other direction. Do it as before, but working on the whole folded strip of fabric. In other words, fold the strip in half end to end and crease the half-way fold, open it out and crease the ¼ lines, etc, remembering to respect the valleys and mountains.

Now you can fold the strip into a neat bundle. Again, this must be done concertina-fashion, folding first one way and then the next. Pop a book on the bundle to keep it in place while you get the resists and clamps ready.

Position one resist underneath the bundle in the position you have planned for your design, then place the other on top of it, lined up perfectly with the first one. Squeeze them tightly together to grip the bundle securely between them and clamp them like this with a clamp at each side, just inside the edges of the bundle. (If you position the clamps outside the bundle then the resists will bow and dye may seep under them. They may even break.) Screw the clamps closed as tightly as you can.

Now for dyeing. Dye as you normally would, or as the instructions that came with the dye tell you. That includes any mordanting, wetting or pre-soaking that might be recommended prior to the actual dyeing, as well as rinsing/washing afterwards.

Don’t release the clamps until the fabric has been fully rinsed. If you are using woad or indigo, the blue colour doesn’t appear until oxygen reaches the dyed fabric and you may find that you need to gently separate the layers of fabric by hand – without removing or loosening the clamps – to get the colour change to happen throughout the entire bundle. Don't rush this.

When you are satisfied that the dye is fast and no more colour will wash out, undo the clamps and shake out the bundle of fabric. Wash and rinse it again, just in case any dye was trapped deep in the folds, then it can be hung up to dry in the normal way. Finally, iron it and get ready for compliments when you wear it.

Variations to try

• Using resists that don't reach the edges of the bundle
• Using resists that aren't rectangular
• Clamping less tightly, or deliberately allowing the resists to bow by clamping near their ends, to let a little colour bleed under the edges
• Over-dyeing with a different colour after removing the resists, adding different ones or folding the bundle differently
• Using resists with a surface texture, such as rough-sawn wood or embossing plates
• Making a triangular bundle by folding the strip (of fabric that has been folded in the first direction) along the diagonal of each tile
• Starting by folding the four corners of a square in to the centre to make a smaller square, then folding as described