In an era where counterfeit products infiltrate nearly every industry — from pharmaceuticals and cosmetics to banknotes and official documents — security inks have become a frontline defense for brand protection. These specialized inks embed verifiable features that are difficult or impossible for counterfeiters to replicate using standard printing equipment. Understanding the different types of security inks is the first step toward building an effective anti-counterfeiting strategy.
UV Fluorescent Inks: The Most Widely Used Covert Solution
UV fluorescent inks are invisible or nearly invisible under normal lighting conditions but emit a bright, vivid glow when exposed to ultraviolet (UV) light at specific wavelengths — typically 254nm or 365nm. They are available in two main categories:
Invisible UV fluorescent inks remain completely transparent under ambient light, making them ideal for hidden security marks on product labels, packaging, and certificates.
Colored UV fluorescent inks appear as a standard color in daylight but shift or intensify under UV light, adding a dual-layer verification feature.
These inks are compatible with screen printing, offset printing, and inkjet processes, and are widely used for tax stamps, ID cards, brand labels, and event tickets.
Infrared (IR) Inks: Machine-Readable Security
Infrared inks respond to infrared light rather than UV. Some formulations absorb IR wavelengths (infrared-absorbing inks), while others emit fluorescence under IR excitation. Because IR features cannot be detected by the naked eye and require specialized readers, they offer a higher level of covert security. IR inks are commonly layered with visible inks on banknotes, passports, and high-value documents to enable automated authentication at inspection points.
Optically Variable Ink (OVI): Color-Shifting Overt Protection
Optically variable inks, also known as color-shift inks, change their perceived color when the viewing angle changes — for example, shifting from green to gold or magenta to green. This effect is achieved through multi-layer interference pigments with precisely controlled thickness. OVI is a classic overt security feature instantly recognizable by consumers without any tools, which is why it has been a staple on global banknotes for decades.
Thermochromic Inks: Temperature-Activated Verification
Thermochromic inks change color reversibly or irreversibly in response to temperature fluctuations. A simple rub between fingers can activate the color shift, making them extremely convenient for on-the-spot authentication. They are often used on food packaging, pharmaceutical labels, and promotional materials where quick consumer-side verification is desired.
Solvent-Sensitive and Fugitive Inks: Tamper-Evident Defense
Solvent-sensitive inks are designed to bleed, smudge, or change color when exposed to common solvents such as alcohol, bleach, or acetone — chemicals frequently used by counterfeiters to alter documents. Fugitive inks, by contrast, dissolve or run when exposed to water. Both types serve as tamper-evident features on certificates, checks, and important legal documents.
Choosing the Right Combination
Modern anti-counterfeiting strategies rarely rely on a single ink type. The most robust solutions combine overt features (visible to consumers), covert features (detectable with simple tools like UV lamps), and forensic features (requiring lab analysis). This layered approach dramatically raises the barrier for counterfeiters.
At ChengBian Chemical, we offer a full portfolio of security inks — including UV fluorescent, IR, thermochromic, and optically variable formulations — tailored for screen printing, offset, and digital inkjet applications. Whether you need a basic invisible UV mark or a multi-layered banknote-grade security system, our technical team can help you select the right combination for your product and budget.