nichwell logo

An Engineer’s Guide to Choosing Security Printing Pigments for Anti-Counterfeiting Inks

In Level 2 covert authentication for banknotes, tax stamps, and official IDs, the exact choice of security printing pigments dictates the success or failure of the entire system.
For security ink formulators, selecting the right luminescent marker goes far beyond simply matching a color. Binder compatibility, particle size distribution, and printing rheology directly determine how the ink behaves on press. Most importantly, these factors decide the absolute invisibility of the print under standard daylight.
Drawing on our engineering experience, Nichwell outlines three critical metrics to evaluate when selecting anti-counterfeiting pigments for your next formulation project.
security-printing-pigments-for-covert-inks

1. Standard Security Inks: Balancing Invisibility and Rheology

When developing covert inks for paper documents or packaging, your primary goal is near-zero daylight visibility coupled with an intense fluorescent yield under blacklight.
  • The Formulation Solution: Nichwell Series 1 (365 nm Organic UV Fluorescent Pigments). Designed specifically for offset, flexographic, and gravure systems.
  • The Physics of Invisibility: What makes an ink truly invisible? It is all about refractive index (RI) matching. Our organic security markers are engineered to closely match the RI of standard acrylic or polyurethane binders. This prevents light scattering at the particle boundary, eliminating any hazy or white appearance on the substrate.
  • Strict Emission Control: We control batch-to-batch spectral precision rigorously. For instance, our red grade maintains a strict peak at 610±5 nm. We even offer a unique dual-peak white (449 nm and 539 nm) for advanced brand protection.
  • Tailored Particle Size: To avoid anilox roller clogging and plate wear in high-speed flexo or offset runs, we provide fine powder options with a strictly controlled D50 of 1–15 µm. Sub-micron dispersion guarantees flawless ink transfer.

2. High-Level Covert Verification: The 254nm Barrier

National-level security documents require features that general counterfeiters cannot easily access. Since standard 365nm UVA lamps are widely available, high-security applications rely on short-wave excitation.
  • The Formulation Solution: Nichwell Series 3 (254 nm Short-Wave Pigments).
  • High Technical Barrier: These specialized security printing pigments (available in both organic and inorganic chemistries) remain dormant unless exposed to specific 254 nm UVC radiation. The required specialized detection equipment makes reverse engineering exceptionally difficult.
  • Forensic Precision: Designed for dual-band verification, our organic 254nm grades feature a tight particle size of 2–6 µm. This ensures high-definition forensic marking on passports and excise stamps. (Safety Note: Appropriate shielding must be used during R&D testing with 254nm UVC sources).

3. Demanding Matrices: Heat Resistance and Zero Bleed

Conventional organic dyes degrade quickly during plastic injection, polymer masterbatch extrusion, or ceramic coating curing. They suffer from thermal quenching and solvent bleeding.
  • The Formulation Solution: Nichwell Series 2 (365 nm Inorganic Pigments).
  • Extreme Thermal Thresholds: Built upon robust inorganic rare-earth complexes, these pigments survive where others burn out. Depending on the color grade, they offer thermal stability ranging from 250∘C up to 600∘C.
  • Zero Migration: Series 2 provides maximum lightfastness and zero dye migration. This makes them the perfect taggant for high-temperature resins (PP, PE, PC) and exterior industrial markers.

Validate Your Application with Nichwell

Ultimately, the performance of any covert materials depends entirely on how they interact with your specific binder formulation and curing process. Theoretical data is helpful, but physical prototyping is mandatory.
Get your tailored evaluation kit today.
Tell our engineers your project parameters, and we will cross-reference the exact grade you need. Please provide:
  1. Target Excitation (365nm or 254nm)
  2. Desired Emission Color & Wavelength
  3. Binder System (e.g., UV-curing Varnish, Solvent-based PU)
  4. Maximum Processing Temperature
Contact the Nichwell Technical Team to Request Your Sample and TDS

(Disclaimer: Technical data provided are typical reference values. Final covert performance varies by ink formulation, substrate, and processing limits.)

Blank Form (#3)