A Guide to Mordant Printing: Step-by-Step Process, Materials and Techniques

What is Mordant Printing?

Mordant printing is the process of applying a mordant (a metal salt  that bonds pigment to fiber) in a thickened form to a fabric. This allows you to create controlled designs or patterns on fabric using natural dyes. Mordant printing allows you to directly paint or print onto the fabric with a thickened paste made from metal salts like alum, combined with other ingredients to attract the pigment to specific areas on your fabric.

The benefits of mordant printing are many: it gives you flexibility in design, allows for complex color application, and offers a unique way to experiment with natural dyes.

Materials Needed for Mordant Printing

This recipe and more information can be found in The Art and Science of Natural Dyes. Before starting your mordant printing project, gather the following materials and tools:

Ingredients:

1. Aluminum Sulfate or Potassium Aluminum Sulfate (20 grams)
• This metal salt helps brighten natural dyes.
2. Soda Ash (10 grams)
• Soda ash is an alkaline substance that assists in activating the mordant process.
3. White Vinegar (approximately 168 grams)
• Vinegar is used to activate the chemical reaction when combined with aluminum sulfate and soda ash.
4. Guar Gum (2 grams)
• A natural thickener that gives the mordant paste its consistency. You can adjust the amount based on the thickness desired.
5. Calcium Carbonate (10 grams per liter of warm water)
• Used in the “dung bath” to remove the guar gum from the fabric after printing.

Mixing Tools:

• Rubber Gloves
• Protect your hands, especially from the metal salts.
• Mask
• To avoid inhaling any fine powders.
• Gram scale
• To measure out your ingredients
• Whisk and large bowl
• To mix them up
• Sealable container
• Print pastes can be kept sealed in the fridge for 3-5 days.
• Immersion Blender (Optional)
• For faster mixing of guar gum into the paste (if you're preparing a large batch).
• Fabric (Cotton, Linen, or Other Natural Fibers)

Application Tools:

• Paintbrush and stamps
• For applying the mordant paste to fabric.
• Painter's Tape 
• Ideal for creating stripes, stencils, and simple designs.
• Screen Printing Frame and Squeegee 
• To screen print your design onto fabric.

• Get creative! 
• Print with leaves, grasses, rocks... 

Step-by-Step Guide to Mordant Printing

Step 1: Prepare Your Mordant Paste

1. Measure Out the Aluminum Sulfate:
   Start by measuring 20 grams of aluminum sulfate or potassium aluminum sulfate. This is the key mordant that will brighten your natural dyes.
2. Measure Out the Soda Ash:
   Measure 10 grams of soda ash and add it to the aluminum sulfate. Dissolve the aluminum and soda ash in a small amount of warm water.
3. Add White Vinegar:
   Measure about 168 grams of white vinegar. Slowly pour the vinegar into the aluminum sulfate and soda ash mixture. As you add vinegar, the mixture will bubble—this is a chemical reaction as the solution neutralizes, so make sure to add the vinegar slowly to avoid overflow or a ‘volcanic’ eruption.
4. Stir Carefully:
   Stir the solution gently while the vinegar is being added. The bubbling will subside as the vinegar neutralizes the reaction.
5. Thicken with Guar Gum:
   In a separate container, measure out 2 grams of guar gum. Gradually add the guar gum to the liquid mixture, stirring constantly to avoid clumping. Guar gum thickens quickly, so add it slowly until you achieve a paste-like consistency.
6. Let the Paste Rest:
   After mixing, let the paste sit for about 30 minutes to allow the guar gum to thicken.

Step 2: Apply the Mordant Paste

Now that your paste is ready, it’s time to apply it to the fabric.

1. Prepare Your Fabric:
   Lay your fabric flat and make sure it’s clean and dry. Natural fibers like cotton, linen, and silk work best for mordant printing.
2. Apply the Paste:
   Use a paintbrush, squeegee, or screen printing frame to apply the thickened mordant paste to your fabric. You can also use painter's tape to create patterns, stripes, or stencils. Trace a lead you found! Be creative with your designs!
3. Let the Paste Dry:
   Allow the paste to dry completely on the fabric before proceeding to the next step. If you’re working outside, air drying in the sun works well.

Step 3: Remove the Gum

After the paste has dried, it’s time to remove the excess guar gum to prepare your fabric for dyeing.

1. Prepare the Dung Bath:
   In a container, mix 10 grams of calcium carbonate with 1 liter of warm water to create a "dung bath." This solution will remove the guar gum from the fabric.
2. Soak the Fabric:
   Submerge the printed fabric into the dung bath for a few minutes. The calcium carbonate will help break down the guar gum, leaving only the metal salt mordant on the fabric.
3. Rinse and Dry:
   After soaking, rinse the fabric thoroughly in cold water to remove any remaining residue. Let the fabric air dry completely.

Step 4: Dye your Fabric

Now that your fabric is printed, you can add color using your favorite natural dye. The mordant paste will attract the dye pigments, creating a permanent bond between the fabric and the color.

1. Prepare Your Dye Bath:
   Follow the instructions for your chosen natural dye (e.g., cochineal, madder, or weld). Keep in mind that mordant printing does not work with indigo alone, but it works well with other natural dyes.
2. Dye the Fabric:
   Submerge the mordanted fabric into the dye bath. The areas that were printed with the mordant paste will absorb more dye, bringing out your printed patterns.
3. Rinse:
   Once the fabric has reached the desired color, remove it from the dye bath and rinse it in cold water.  

Tips for Successful Mordant Printing

• Test the Paste: Before working on a large piece of fabric, test the mordant paste on a small swatch to see how it reacts with your chosen dye.
• Use Different Application Techniques: Experiment with various tools like brushes, sponges, or stamps, or even rocks, leaves, and grasses, to create different textures and patterns.
• Reuse Your Tools: Painter’s tape and screen printing stencils can be reused multiple times.

Start with these basic steps, experiment with different designs, and soon you'll be creating beautiful, hand-printed fabrics using the magic of mordant printing. Happy printing!

Watch Along: Mordant Print Mixing and Application