2016-02-21

security inks ...

machins have been printed with many different inks, and papers.  special pigments : Iriodin and rhodamine are examples ...

UV Fluorescent
These inks are normally invisible as printed but fluoresce under UV light. There are two types; single long wavelength (360 nm) and dual which fluoresces one color under short wavelength UVa (250 nm) and a different color under log wavelength UVc (360 nm). Typical UV fluorescent color inks include yellow, green, blue, orange, and red. These inks are often used in banknote printing. This ink is available for wet or dry offset, flexographic and gravure printing.

UV Phosphorescent inks also are used in different colors as modern presses operate at higher speeds, quality control is moderated by UV-curing process.   machins are 3 cylinder process - value / phosphor / iriodin layers ...


modern machin presses are using a variety of pigments and flourescent or  phosphorescent inks ...  the counterfeit machins exhibit their own group of flourescent pigments and inks.





in exploring our collections, we reveal some unusual UVa or UVc reactions on genuine and forgery items ...

LuminoChem  shows many inks under 258/365/980 nm lite sources.   raman spectroscopy uses varied light colors in analysis.   interesting addition to collecting experience.