Suminagashi Paper Marbling: Learn the Secret of the Suminagashi Technique

Suminagashi Paper Marbling: Learn the Secret of the Suminagashi Technique

July 14, 2025

If you’ve ever dipped a brush into Suminagashi ink and watched the swirls bloom across water, you already know how magical this technique is. But if you've struggled with dull prints or patchy results, there might be one game-changing step you’re missing: alum.

In this post, we’ll break down the Suminagashi technique, including the materials you'll need, a simple step-by-step process, and tips for success, particularly when using alum (potassium aluminum sulfate) to prepare your paper. I tested different paper weights with and without alum, and the difference was more obvious than I expected.

What Is Suminagashi?

Suminagashi is the ancient Japanese art of marbling paper using floating inks. The word means "floating ink," and that's exactly what happens. You drop ink onto the surface of water and watch it spread into rings and patterns, then you place your paper onto the surface to transfer the design. Each print is one of a kind.

It’s beautiful, a little unpredictable, and completely addictive.

Materials You'll Need

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You don’t need fancy equipment to get started. Here's what I used:

  • Suminagashi Marbling Ink (available on Amazon)
  • Two brushes (available on Amazon) – one for soapy water, one for ink
  • A dish of water (a shallow tray works best)
  • Soapy water (just a drop of dish soap in water)
  • Stick or skewer for swirling patterns
  • Newspaper (for cleaning ink off the water surface)
  • Various paper weights:
    • 20 lb copy paper
    • 32 lb copy paper
    • 80 lb drawing paper
  • Alum (Potassium Aluminum Sulfate) – mixed with water and applied to one side of the paper

Suminagashi Technique Alum to improve prints

Step-by-Step Instructions

1. Prep Your Paper

Coat one side of each sheet of paper with a solution of alum and water using a flat brush. Let it dry completely. This step instantly fixes the ink to the paper and can make a big difference in clarity and color vibrancy.

Tip: Mark the back of each alum-coated sheet to keep track.

Suminagashi technique prep paper with alum

2. Set Up Your Workspace

Fill a shallow tray with clean water. Take a newspaper strip and run it across your tray of water to help remove dust and debris.

Prepare suminagashi water for ink

3. Load Your Brushes

Use one brush dipped in soapy water and the other in your chosen ink color.

Suminagashi alternating brushes. Ink and soapy water

4. Begin Your Pattern

Alternate tapping the surface of the water with the ink brush and the soapy water brush. The soap causes the ink to spread outward, creating expanding rings. Keep alternating until you have a pattern you like. Use your skewer/stick/straw to create our pattern of swirls.

You can also try dropping ink directly from the bottle and swirling with a stick for a different effect.

Suminagashi ink and soapy water technique

5. Pull the Print

Gently lay your paper onto the water’s surface, coated side down. Tap lightly to avoid air bubbles (they’ll leave blank spots). Then lift the paper and set it aside to dry.

Repeat using different paper weights and with/without alum to compare your results.

Pull your print for your suminagashi pattern

Tips for Success

  • Use clean water between prints for best results.
  • Apply alum to only one side of the paper and keep track of it.
  • 20 lb paper with alum surprised me—it held up better than expected.
  • Avoid air bubbles by laying the paper flat and tapping gently.
  • Try both controlled and loose patterns—you’ll learn what you like best.
  • Alum makes colors richer and sharper. Without it, prints can look dull or washed out.

Conclusion: Is Alum Worth It?

After testing 20 lb, 32 lb, and 80 lb papers with and without alum, the answer is clear—alum helps. Prints on alum-coated paper had more vibrant color, sharper lines, and overall looked more professional. While some no-alum prints still turned out okay, they lacked the clarity and richness of their treated counterparts.

I’ll definitely be adding alum to my regular paper-preparing ritual, and I plan to test it with other paper dyeing methods as well.

If you’ve tried Suminagashi before or you’re just getting started, consider giving alum a try. And let me know in the comments what worked best for you?

Thanks for following along with this experiment. For a complete step-by-step video tutorial, please check the description for the link.

See you in the next video!

 

Disclosure: This post may contain affiliate links; when clicked, we may earn a small commission at no additional cost to you.

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