How to Prevent Dye Migration in Screen Printing on 100% Cotton Tees

Screen printing on t-shirts is the best way to create vibrant, custom designs, but sometimes issues like dye migration can throw a wrench in your plans.

If you’ve ever printed white ink on a faded-style 100% cotton t-shirt only to see it turn pale pink after curing, you’ve likely encountered dye migration. This happens when the shirt’s dye bleeds into the ink, changing its color.

Don’t worry—this blog will explain what dye migration is and share simple ways to prevent it when screen printing on 100% cotton tees. Let’s get started!

What Is Dye Migration?

Dye migration occurs when the dye in a t-shirt’s fabric moves into the ink during or after the printing process, especially when heat is applied to cure the ink. This is common with garment-dyed or faded-style t-shirts, particularly red or dark-colored ones.

The result? Your crisp white ink might turn pink or another off-color, ruining the design. Even 100% cotton tees can have this issue if they’re dyed with certain types of dyes, like Vat Red 41, which can act similarly to dyes used in polyester fabrics.

Why Does Dye Migration Happen on Cotton Tees?

You might think dye migration is only a problem for polyester or blended fabrics, but that’s not always the case. Some cotton t-shirts, especially those with a faded or vintage look, are garment-dyed, meaning the fabric is dyed after the shirt is made.

This process can leave dyes that are less stable and more likely to bleed into your ink. If the shirts aren’t rinsed properly after dyeing, loose dye particles can also mix with your ink during curing, causing discoloration.

Can You Use a Poly Blocker on 100% Cotton?

A common question is whether a poly blocker—a type of ink underbase designed to prevent dye migration in polyester fabrics—can be used on 100% cotton tees. The answer is: it’s not ideal, but it’s possible in some cases. Poly blockers are formulated for polyester because they counteract the disperse dyes commonly used in those fabrics.

However, some cotton tees dyed with certain dyes (like Vat Red 41, also known as Disperse Red 364 in polyester) can behave similarly, so a poly blocker might be recommended by the shirt manufacturer. That said, poly blockers can sometimes cause issues on cotton, like poor adhesion or unwanted chemical reactions, so they’re not always the best choice.

What are the Better Solutions for Preventing Dye Migration?

To keep your white ink bright and prevent dye migration on 100% cotton tees, try these methods:

Use a Grey or Black Dye Blocker: Instead of a poly blocker, opt for a grey or black dye blocker underbase. These are regular plastisol inks designed to block dye migration and work well on cotton. Print the dye blocker as an underbase, then apply your white ink on top. This creates a barrier that stops the shirt’s dye from bleeding through. Brands like Wilflex or Rutland offer reliable dye blocker inks.
Try Low-Bleed White Ink: Low-bleed white plastisol ink is formulated to resist dye migration. It’s a good option for cotton tees with problematic dyes. Check with your ink supplier to ensure you’re using a high-quality low-bleed ink suited for cotton.
Mix Plastisol with Discharge Base: For a softer print, mix white plastisol ink with a discharge base. Discharge ink removes the shirt’s dye and replaces it with your ink color, reducing the chance of migration. This method also gives your print a smooth, soft feel, which is great for faded-style tees.
Use Silicone Inks: Silicone-based inks are another option. They’re less likely to absorb dyes from the fabric and work well on cotton. They’re also durable and stretchy, making them a good choice for high-quality prints.

What Are the Tips for Successful Printing?

To minimize dye migration and ensure a great print, follow these practical tips:

Choose High-Quality Shirts: Not all 100% cotton tees are created equal. Some cheaper shirts may be labeled as 100% cotton but contain trace amounts of polyester or have poorly rinsed dyes. Stick with reputable brands and check their website for printing recommendations. If the manufacturer suggests a poly blocker, they may know their dyes are prone to migration.
Test Before Printing: Always print a test shirt before running a full batch. Cure the ink and check for color changes. If you see pink or other discoloration, try a different ink or underbase.
Adjust Curing Settings: High curing temperatures can worsen dye migration. Use the lowest effective temperature to cure your ink, and follow the ink manufacturer’s guidelines.
Wash the Shirts First: If possible, wash the tees before printing to remove loose dyes. This can reduce migration, especially on garment-dyed shirts.

Final Thoughts

Dye migration can be a frustrating issue when screen printing on 100% cotton tees, but it’s manageable with the right approach. Instead of relying on a poly blocker, which may not be ideal for cotton, use a grey or black dye blocker, low-bleed white ink, or alternative inks like silicone or discharge-based plastisol.

Always test your setup and choose high-quality shirts to minimize problems. With these tips, you’ll be able to print vibrant, clean designs without the dreaded pink tint.