Lesson 4: Understanding Chemicals

The chemicals of batik have been the hardest to understand, and for the painterly batiks that my group are doing, I have had to make a great many errors to discover perfect solutions to uncommon situations. If there is any lesson you should read about, this is the most important one.

The most important chemical in the batik process is soda ash, a fixative that bonds the dye to the fiber. Dye must be 'fixed' (made permanent) with Soda Ash on cotton and other cellulose fibers. It's a mild alkali that enables the reaction between the dye and the cellulose fibers at lower temperatures, causing them to “become one.” How much you use is normally a function of the amount of water, not the amount of fabric or dye.

I have ready many books on batik, and every one of them has instructed presoaking your fabric in a mixture of soda ash and water and then letting it dry completely dry before sketching your image. When the dye is painted on, it reacts with the Soda Ash in the fabric.
 
This technique is fine if you are creating simple "blocky" images or stamps of traditional batik that don't require intensive painting, but I have found that the more detailed painting I do leaves a stain caused by diffusion. The wet areas of dye seem to push the sodium of the soda ash to the border and leave and unsightly stain. Stay tuned and you will learn a very important simple trick.

BASE SOLUTION: Cold Batch Chemical Water

Hand painting on fabric requires a thickened solution that slows bleeding, allowing you greater control of color placement and blending. First, you need to create the base solution for the other chemicals that will be added later. Cold batch chemical water is the base for mixing dyes for the purpose of handpainting and can be stored in a refrigerator for up to a month. It basically contains water and Urea. Urea extends the drying time of the fabric so that the dye has time to bond with the fibers, generally 6 hours for pastels or silk OR 12-24 hours for deeper shades and brighter colors

Cold Batch Chemical Water Recipe:

Mix together ¾ cup Urea (dissolve in a little hot water if necessary) with 1 quart water. (NOTE: In this image, I am only making a quarter batch because that is all I need during my month long sojourn with my twin sister in Colorado.)

THICKENING SOLUTION: Sodium Alginate

Before handpainting, the chemical water needs to be thickened. The thicker the solution, the less it will bleed along the fabric fibers, allowing you to control the flow and actually paint or print onto the fabric.

Thickener is generally made from sodium alginate, which is cheaper but requires mixing in a blender, some time to thicken, and has a yellowish cast that may skew color perception slightly (from what you see when wet to what you see when dry). I used to buy a pre-made clear mixture called Superclear from Dharma Trading Company, but supply shortages on alge has made this difficult to get in the United States. If this is a concern, you can buy a higher grade food alginate used in molecular gastronomy at Amazon.

Sodium Alginate Recipe:

In a blender, combine 1 cup chemical water and 2 Tablespoons sodium alginate powder. Mix at low speed for 10 minutes. Refrigerate for several hours or overnight until thickened. Store in the refrigerator. If you want a thicker solution (especially for screen printing), add more sodium alginate.

SODA ASH: ***The BIG Secret***

After my initial failure with staining caused by diffusion, I decided to try adding in a little bit of soda ash when I mixed the dyes and thickened solution together. That was a failure. It was difficult to control the ratio of liquid to soda ash to get the correct reaction with the fiber.

Sadly, I do my best thinking when I am asleep (and might benefit from sleeping a bit more often). In a moment of inspiration, I jumped out of bed in a EUREKA moment. The soda ash reacts with the dyes!!!! The solution is to add the soda ash to the thickened solution where it remains inactive at the proper concentration until the dye is combined with it.

Soda Ash Recipe:

Roughly ½ teaspoon soda ash per ½ cup of thickened chemical water is needed. If you don't use enough, the dye won't yield full strength.

When mixed with the dyes, the soda ash fixer activates and has a limited shelf life of 3-5 hours before it becomes half as effective. Blacks exhaust even faster. Only small quantities of dye solutions are needed for painting.

Add a squirt of thickened chemical water (or however much you will need for your image) into a mixing cup. Dip the tip of a paintbrush into the powdered dye and mix a small quantity of it into the thickened chemical water. Test out the color on a scrap piece of cloth or paper towel. Try to go a shade or two darker than you want for your finished result. Use slightly more for blacks, bright reds, and bright blues. Smaller dye to water ratio yields pastel hues.

MISCELLANEOUS CHEMICALS:
Calsolene oil is used in the final deep water dye bath to break the surface tension of the water and allow the dye to dissolve better.

Synthrapol is a wetting agent that helps wool fibers to open up to absorb water for the acid dye process. However, for cold water batik Synthrapol is used as a soap to encapsulate loose dye particles and prevent accidental dye spots when washing your batik before boiling the wax out.

The next lesson I will present will be about different techniques in painting with thickened dyes.