Printing on polyester and polyester blends can be a unique challenge for screen printers, especially when it comes to dye migration. If you’ve ever seen bright whites turn pink on a red polyester shirt or noticed a design fade or change color after a few days, you've experienced dye migration. In Deep Dive with Colin, we’ll explain why dye migration happens, how to prevent it, and the best tools to keep your prints looking vibrant.
UNDERSTANDING DYE MIGRATION
Dye migration happens when the dye in polyester fabric seeps into the ink layer, causing the colors to change. Polyester fabrics are often dyed with low-energy or high-energy dyes, which are heat-set at different levels. Low-energy dyes are more prone to reactivation under the heat of the printing process, causing the dye to bleed into the ink.
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Sublimation and migration are terms often used in this context. Sublimation is when heat causes dye particles to turn into gas and shift into the ink layer, usually happening right in the dryer or during flashing. Migration is a slower process where dye particles gradually make their way through the ink, which can take days or even weeks to become noticeable.
WHY DYE MIGRATION IS COMMON WITH POLYESTER
Polyester fabrics are created from white threads that are dyed to achieve vivid colors. The dye’s stability depends on its energy level; high-energy dyes resist reactivation and migration, while low-energy dyes reactivate more easily with heat. This reactivation becomes a problem during the printing process when heat from curing or flashing can cause the dye to re-gasify and migrate into the ink layer above it.
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ESSENTIAL TOOLS FOR PREVENTING DYE MIGRATION
To keep dye migration under control, the right tools and techniques are key. Here’s what can make the biggest difference in the printing process.
POLYESTER WHITE INK
Polyester white inks are specially formulated to resist dye migration. They are thicker and heavier than standard white inks, which may require extra effort to stir and apply. Investing in a high-quality polyester white ink can save time, reduce reprints, and improve final print quality.
BARRIER BASE (BLOCKER)
For challenging fabrics, a barrier base is extremely useful. This base layer acts as a shield, stopping the dye from reaching the ink layer above. Barrier bases are typically gray or black and contain activated charcoal, which traps dye particles within microscopic pores, preventing them from moving up into the ink.
A thicker layer of barrier base can make a significant difference. Printing this base with a low mesh count screen (86–110) will ensure enough ink is deposited to block the dye. Too thin a layer might not trap all the dye particles.
TIPS FOR CONSISTENT, HIGH-QUALITY RESULTS
Mesh count is crucial when applying the barrier base. A lower mesh count helps create a thicker layer that will block more dye particles. Additionally, applying a white underlay over the barrier base provides extra protection and prevents colors from shifting.
Using high-quality inks and bases is another essential factor. Cheap inks may save money upfront but are more likely to experience dye migration. High-quality polyester whites and barrier bases significantly reduce dye bleed, keeping prints sharp and bright over time.
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Barrier inks sometimes feel gritty due to the activated charcoal particles they contain. This texture is normal and won’t impact the ink’s performance. The particles can even vary slightly between batches without affecting the ink’s function.
MANAGING DYE MIGRATION IN MULTICOLOR DESIGNS
When printing multicolor designs, dye migration can be particularly challenging. A good way to visualize the approach is to think of the layers like bricks in a wall, stacked up precisely to prevent any dye seepage. Each color should be applied on top of the barrier and white layers, with careful attention to registration.
Using barrier black or gray ink serves different design purposes. Barrier black is ideal for dark designs, as it provides strong contrast, though it usually requires a white underlay for lighter colors. Barrier gray can work for lighter designs and might allow colors to be printed directly on top. However, without a white underlay, some colors may shift even on a gray base.
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FINAL THOUGHTS ON POLYESTER PRINTING
Polyester printing can be tricky, but understanding dye migration and how to prevent it will keep your designs vibrant and lasting longer. By using quality polyester white inks, a barrier base, and managing your screen mesh count carefully, you can confidently tackle polyester printing and create prints that look amazing.
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