How to Mix UV Fluorescent Ink: Formulations, Steps, and Stability Control

High-quality security printing relies heavily on precise ink formulations. While formulating ink, the most critical component is the UV fluorescent pigment. This specialized material stays invisible under natural light but glows brightly under 365nm or 254nm UV light. However, formulators often face production issues such as low brightness, ink clumping, and pigment migration.

However, manufacturers often face issues during actual production. These include low brightness, uneven glowing, ink clumping, loss of glow after storage, and ink migration. Most of these problems stem from imprecise formulations, poor dispersion, or weak stability control.
This guide shares a production-tested mixing method. It balances batch consistency with long-term storage stability. Even beginners can easily master the process by following these steps.

1. The Core Principle of UV Fluorescent Ink

UV fluorescent ink is fundamentally different from regular color ink. It relies entirely on a system of a UV-fluorescent pigment and a transparent resin binder.
Critical Rule: Never add opaque fillers like titanium dioxide, carbon black, or talcum powder. These materials block UV light, quench fluorescence, and drastically reduce brightness.
High-quality UV fluorescent ink must meet three standards:

Even glowing without dark spots.

High brightness under UV light.

Strong resistance to fading and migration during storage.

Achieving this requires a standardized mixing process. The industry mainly uses solvent-based and water-based systems. Both adapt well to screen printing, pad printing, coating, and gravure printing.

2. Standard Formulation Ratios (For Mass Production)

You can tweak these ratios based on your printing methods and brightness needs. They work well for most security and invisible printing needs.

1.Solvent-Based UV Fluorescent Ink

Best for screen/pad printing. Offers great stability on paper, PVC, PET, and plastics.

Component	Percentage	Notes
UV Fluorescent Pigment	8% – 18%	Use 8%–12% for standard security; 12%–18% for high-brightness thick coatings.
Transparent Binder	60% – 75%	Neutral transparent resin (acrylic or polyamide varnish).
Special Dispersant	1% – 3%	Prevents pigment clumping and improves uniformity.
Light Stabilizer & Antioxidant	0.5% – 2%	Delays UV aging and reduces loss of glow during storage.
Thinner/Solvent	Balance	Ethyl acetate or isopropyl alcohol to adjust viscosity.

2.Water-Based UV Fluorescent Ink

Eco-friendly and low odor. Ideal for food packaging and creative crafts.

Component	Percentage
UV Fluorescent Pigment	8% – 15%
Water-Based Transparent Acrylic Emulsion	65% – 75%
Water-Based Dispersant & Wetting Agent	1.5% – 3.5%
Water-Based Light Stabilizer	0.3% – 1.5%
Deionized Water & Co-solvent	Balance

Formulation Warnings

Avoid Overloading: Do not add more than 20% pigment. Higher concentrations cause quenching. This dims the glow and causes the ink to clump.

Avoid Acidic Resins: Acid-base imbalances destroy the conjugated structure of fluorescent molecules. This leads to an irreversible loss of glow.

3.Step-by-Step Mixing Process

Always follow these rules: keep away from light, maintain low temperatures, use low-speed wetting, disperse thoroughly, and avoid over-milling.

Step 1: Prepare Raw Materials and Tools

Clean all mixing containers, stirring equipment, and filters. Ensure there is zero residue from regular inks. Check the pigment quality before use; do not use clumped or damp pigments. Work in a dark room to protect materials from direct natural or UV light.

Step 2: Dissolve the Base Resin

Pour the transparent varnish or water-based emulsion into the container. Stir at a low speed of 500–800 rpm. Slowly add the solvent or deionized water until the mixture flows smoothly and turns transparent. Keep the temperature under 60°C. High heat degrades fluorescent dyes and ruins their glowing performance.

Step 3: Add Auxiliaries

Add the dispersant, light stabilizer, and antioxidant one by one. Stir continuously for 5–10 minutes. This blends the additives thoroughly into the resin. These additives stop pigment migration, prevent aging, and boost ink stability.

Step 4: Add Pigment Gradually (Low-Speed Wetting)

Key Tip: Never dump all the pigment in at once.

Slowly add the UV fluorescent pigment in 3 to 5 separate batches. Stir at low speed for 10 minutes to let the resin fully coat the pigment. Next, ramp up the speed to 1500–2500 rpm and disperse quickly for 20–30 minutes. This prevents high local concentrations, reducing the risk of quenching and white clumps.

Step 5: Mill for Finiteness

For mass production, use a horizontal bead mill with small zirconium beads. Control the ink fineness based on your printing process: ≤15-20um for screen and pad printing, and ≤5-10um for gravure printing or coating. For small batches, you can extend the high-speed dispersing time instead. Do not over-mill. Excessive milling breaks the protective polymer shell of the pigment, lowering its weather and migration resistance.

Step 6: Adjust Viscosity, Filter, and Age

Adjust the viscosity based on your printing style. Screen printing ink should be thicker, pad printing thinner, and coating ink right in the middle. Pass the formulation through a 400-mesh micron filter bag to eliminate larger aggregates and impurities. Finally, seal it away from light and let it age for 8–12 hours (or overnight). This allows microbubbles to escape completely and stabilizes the polymer network before printing.

Need high-purity raw materials for this formulation? Explore our 365nm UV Fluorescent Pigments featuring double-layer silica coating for zero quenching.

4.Pro Tips for Better Brightness and Stability

To Boost Brightness

Choose UV fluorescent pigments with a double-layer silica coating. Nichwell 365nm UV Pigments offer outstanding color purity and stability, explicitly designed to prevent concentration quenching

To Prevent Glow Loss and Aging

Combine light stabilizers with antioxidants in your formula to fight UV light and oxygen damage. Always seal and store the ink in dark places to stop long-term light exposure from fading the glow.

To Prevent Migration and Bleeding

Avoid resin systems that contain high levels of plasticizers. Choose modified fluorescent pigments that feature complete encapsulation coatings. Keep the ink drying temperature under 80°C. Low-temperature curing stops the pigment from separating, which prevents surface whitening or color bleeding.

5.Troubleshooting Common Issues

Issue	Likely Cause	Solution
Splotchy glow or white spots	Poor dispersion; clumped pigments.	Extend high-speed stirring time, use the right dispersant, and filter thoroughly.
Dim glow or low brightness	Too little pigment; hidden impurities; high resin acid value.	Adjust the pigment ratio, switch to a neutral transparent resin, and check material purity.
Glow fades after days of storage	Missing light stabilizers; light exposure; acid-base imbalance.	Add the right stabilizers, seal the ink away from light, and keep the system neutral.
Ink migration or white surface powder	Broken pigment coating; low resin softening point; over-milling.	Switch to high-quality coated pigments, optimize milling times, and use dedicated binders.

6. Storage and Handling Notes

Storage Environment: Pack final inks in black, light-blocking sealed drums or vacuumed aluminum foil bags. Store them in a cool, dry place between 10–25°C with 40%–60% humidity. Keep them away from heat sources and acids or bases.

Usage Window: Use the ink quickly once opened. Reseal any leftover ink immediately away from light to limit contact with air and light.

Drying Process: Avoid baking the prints at high temperatures for long periods. A moderate-to-low curing temperature preserves pigment stability and extends the print’s lifespan.

Formulation is the bedrock of high-quality UV fluorescent ink, but dispersion and storage are just as vital. By avoiding concentration overload, over-milling, light aging, and contamination, you can create a top-tier fluorescent ink. This standard process ensures excellent brightness, even glowing, and strong resistance to aging and migration across all security printing applications.

Source UV Fluorescent Pigments Directly from the Manufacturer

Ready to upgrade your anti-counterfeiting ink formulations? Stop guessing with middleman quality. We provide:

Multiple Excitation Wavelengths: 254nm and 365nm pigments.

Vibrant Glowing Colors: Red, Yellow, Blue, Green, Pink, and Invisible Bi-color options.

Global Standards Compliance: Eco-friendly, low-odor, and stable under high production temperatures.

Ready to upgrade your anti-counterfeiting ink formulations?
Stop guessing with middleman quality. Contact Nichwell’s engineering team today to request a 254nm/365nm testing sample and start mixing your perfect security ink.