Blog Post 8: How to Test for Colorfastness in Quilting Cotton

Testing for colorfastness might seem like an extra chore, but it can save your quilt from heartache—especially when working with dark or richly dyed fabrics. A single bleeding fabric can permanently stain lighter ones during washing. The good news? You can easily test your fabric before sewing it into your masterpiece. Here's how to do it—and what to do if the fabric fails.

1. Why Colorfastness Matters

Colorfastness refers to a fabric's ability to hold its dye without bleeding or fading when exposed to water, heat, or friction. Some vibrant colors—especially reds, purples, and navies—are more prone to bleeding, especially if they haven’t been pre-washed or if they're hand-dyed, like batiks. Testing these fabrics before sewing helps ensure your finished quilt remains crisp, clean, and free of unexpected dye transfer.

2. The Damp Cloth Test

The simplest method is the "damp cloth test." Cut a small square of the fabric and place it on a white cloth or paper towel. Dampen another white cloth with warm water, then press it firmly on the colored fabric. Hold for 30 seconds, then lift and inspect the white cloth. If no dye transfers, the fabric is likely colorfast. If you see any bleeding or tint, further precautions are necessary.

3. The Soak Test

For a more thorough check, cut a small piece of fabric (about 4x4 inches) and place it in a clear bowl of warm water. Let it soak for 30 minutes, stirring gently now and then. If the water stays clear, the dye is stable. If it turns noticeably tinted, the fabric is bleeding. Repeat the process until the water remains clear—or treat the fabric with a dye fixative like Retayne before use.

4. What to Do If Fabric Bleeds

Don’t toss that beautiful fabric just yet. If it bleeds but you still want to use it, pre-wash it multiple times in cold water with a dye-catching sheet or Synthrapol, which suspends loose dye in water and prevents it from redepositing onto other fabrics. For persistent bleeding, use a commercial dye fixative. Always test again after treatment to ensure the fabric is ready.

5. Mixing Colors Safely in a Quilt

Even if your fabrics pass the colorfastness test, it’s smart to take extra precautions when washing your finished quilt. Wash in cold water, use gentle detergent, and add a color catcher sheet. Avoid soaking the quilt for long periods, and never wash it with harsh cleaners like bleach or brighteners that can reactivate dyes.

Taking the time to test your fabrics may feel like an extra step, but it’s a small effort that protects the hours of work that go into creating a quilt. With just a little care upfront, you’ll ensure that your finished quilt stays just as vibrant and beautiful as you intended.