JOHN MARSHALL:
works in fabric

A resist may be anything that blocks the application of another medium. The string in "tie-dye" is a resist, as is the wax in batik. A stencil is used to block out areas of the cloth while applying color or paste, and so may also be thought of as a resist.
In the context of katazome, the resist is the paste made from rice bran (komon nuka) and powdered sweet rice (mochiko), plus a few other ingredients added in as needs dictate.

Just as in baking bread or any other cooking endeavor, there are many excellent recipes out there. Find the one you like and stay with it.
Continuing with the analogy, the most basic bread consists of flour and water. Anything more is extra. If you prefer leavened bread, you add yeast. The most basic paste consists of rice and bran. Each element is defined below. Take note of the function of each and vary your recipe according to your particular needs.

BASIC
rice paste resist
RECIPE

one part bran : one part flour : one part water

1. Sift dry ingredients and blend together thoroughly.

Add water gradually, distributing the moisture evenly and thoroughly before adding more. The more time you spend mixing well, the more lump free your paste will turn out.

a bowl too small will make it
difficult to mix the ingredients

2. Add enough water to make the dough the consistency of pie crust dough, or wood putty.

The more time you spend mixing well, the more lump free your paste will turn out.

3. Form little golf ball size shapes from the dough. Place in a steamer lined with a moistened cloth and steam for 30 to 45 minutes, or until done.

So what is done? Done is when the color of the dough ball has changed color all the way through to the core. What color? It should change from about the color of manila paper when you start out to a deeper shade, about the color of peanut butter. However, cooking it until it is as dark as your stencil paper will make a lump perfect for repairing cracks in your foundation, but not viable paste.

So what happens if I undercook it? Undercooking may not be detectable right away. First of all, your paste won't be very elastic while mixing it in the suribachi. Worse than that is when it dries on the cloth after applying it with your stencil or cone: it turns powdery and may even crumble off. Not a very good resist.

suribachi with surikogi nestled inside

4. Transfer the dough balls quickly to a suribachi (mortar) and mix thoroughly and vigorously with a surikogi (pestle).

If you dilly-dally a crust will form and you will get lumps.The more time you spend mixing well, the more lump free your paste will turn out.

5. Begin to add more water slowly to thin the mixture.

As it cools it will thicken threatening to permanently affix itself to your lovely grooved bowl. If you dilly-dally a crust will form and you will get lumps.The more time you spend mixing well, the more lump free your paste will turn out.

6. Continue adding water until it is of a spreading consistency.

It is best to stop while it is a little on the thick side and still a bit warm. As it comes to room temperature it will thicken a bit more, but you may add water just before you're about to use it to bring it to just the right consistency for the project at hand.

So remember: MIX THOROUGHLY, DON'T DILLY-DALLY, AND BY ALL MEANS DON'T GET LUMPS!

7. Transfer to a mixing bowl and cover with plastic wrap, being careful not to trap any air pockets.

Clean all tools used to make the paste as soon as possible, once it hardens in the grooves of the suribachi, it is very difficult to get out.

8. May be refrigerated for a day or two in anticipation of use.

You will know when you've kept it too long. It begins to get yeasty and pets will start to leave the room. It tends to last a bit longer in winter when there are fewer spores in the air.

Don't bother to make enough to freeze. Freezing the paste causes it to take on a brittle, rubbery characteristic. To return it to its elastic state you must recook it, defeating the purpose of mixing some ahead.

pouring paste into
cloth for squeezing

9. Cone method (tsutsugaki): pour paste into handkerchief weight cloth (old sheeting works well) and force out by squeezing.

If even the smallest lump is tolerated in paste for tsutsugaki, you run the risk of having the nozzle clog at the most crucial point of a very delicate design. It is not worth the risk. Filtering the paste through the cloth will remove even the tiniest lump.

The above method works quite well. Having said that, I have found I am able to make much better paste using the microwave.

1. Follow the directions above, however, don't bother with making the small dough balls.

2. Add a little water to a glass mixing bowl and add the entire batch to the bowl as one lump. Force the dough into the bowl until the water rises up the sides, making sure all air pockets are displaced as you proceed. Add enough extra water to cover the top of the paste, but no more than necessary.

If pockets of air are trapped you run the risk of crusting, and by extension, lumps will appear. We don't want lumps. The water displaces the air and removes this risk, hence adding a little water to the top will complete the seal. Too much water will over-thin the mixture, so add only enough to cover the paste and no more - - you may always add more to cover the surface as necessary during the cooking process.

3. Cook on a medium low for about five to ten minutes, depending on the size of the batch. Allow to set for another five or ten minutes (or until you remember it is still in the microwave), and zap it again for a few minutes. Test occasionally to see if it has cooked through to the core. When the color has changed all the way through, continue with step 4. above.

If some of the paste on top should crust, simply remove it with a spoon before adding the mixture to the suribachi for mixing.

Extra ingredients to consider using:

calx (dyer's term): aka calcium hydroxide (purchase from chemist), aka cal (used in making tortillas, konyaku, etc.) aka lime (available through farm supply stores), aka chalk (used on football fields).
Dissolve a little in water (careful: it's very alkaline), add decanted solution to paste in lieu of some of the water. It should turn the paste a little yellow. The right amount will give you paste a little extra elasticity.Too much will make the paste like "silly putty". NOTE: If you live on large limestone deposits you probably won't need to add calx. It's already in your tap water.

table salt: aka table salt. Dissolving a little salt in water and then adding the solution to the paste in lieu of water will help to keep the paste from cracking. Salt draws moisture from the air. Moisture will keep the paste in a more leathery state, helping to keep it a bit more maleable. Too little salt won't be of much help, too much and your paste will never dry. You call it. Don't use any salt on rainy or humid days, use a bit more if you're going to be working outside on a hot windy day.

glycerine: Available through drug stores. Use with, or instead of, table salt. It is an immolient, so it will help to keep the paste leathery without being too influenced by the daily changes in humidity. Add a little. If your paste cracks, add more next time. If you start to get what look like oil bleed lines around the edges of your paste, you added too much.

pigments: You may find it desirable, under certain circumstances to color your paste. This is not intended to act to dye the cloth (as in nassen, or yuzen). Actually, any pigment you add should be totally inert. It is added only to make it easier for you to see the paste as you work on applying the resist to your yardage. Cobalt blue is commonly added as a powder to the paste in Japan to make a bluish tone and stand out in greater contrast to the natural tone of the silk. This helps when working with repeat patterns in particular.