These inks change their chromatic appearance when exposed to a specific energy source. This energy may be light-based or thermal. The effect is usually reversible, though in some cases it may be irreversible.

Types of inks

• Phosphorescent
  • Conventional
  • Security-grade*
• Photochromic
• Thermochromic:
  • Visible to invisible
  • Invisible to visible
  • Bicolor
  • Tricolor
• Iridescent
  • Iridescent
  • Irionew
  • Newchrom (OVI Ink)
  • Satin

Application features
Given their wide range, they can be found in all types of documents. Depending on the technology used, they may be applied in both low- and high-security environments.

Observations
A specific device is needed to verify this ink.

Security level
Medium