UV-induced visible fluorescence

UV-induced visible fluorescence (UVIVF) is a very interesting phenomenon, which uses ultraviolet light to induce subjects to fluoresce in the visible light spectrum. UVIVF imaging requires a dark room so that the only light visible is that which comes from the fluorescence of the subject; the UV light also needs to be blocked by the use of an UV/IR cut filter on the camera lens.

Previously I have been taking UVIVF images of flowers, but I thought I would change subjects this time to something artificial. This phenomenon is used to prevent fraud, as genuine bank notes tend to fluoresce in certain ways when lit by ultraviolet light; this helps to distinguish them from counterfeit notes. In this post, I will be comparing the appearances in visible light, UV, Insect-D-sight and UVIVF, of the part of bank notes with an interesting UVIVF pattern.

First bank note.

Visible
Visible light
UV
UV light (with 365nm torch)
UV - Xenon flash
UV – Xenon flash
IDS1
IDS1 (with 365nm torch)
IDS1 - Xenon flash
IDS1 – Xenon flash
IDS2
IDS2e (with 365nm torch)
IDS2e - Xenon flash
IDS2e – Xenon flash
UVIVF
UVIVF

With the first note, you can notice that the 50 starts to become visible in UV, and the IDS1 lit by UV torch shows up the little tiny fluorescent strips within the notes. But the UVIVF is the most interesting image of all.

A different note.

Visible
Visible light
UV
UV light (using 365nm torch)
IDS2
IDS2 (UV + blue/green)
UVIVF
UVIVF

As you can see, the second note has yellow stars which are UV-dark. But again it is the UVIVF image which is the most interesting. I always liked UVIVF as the images can be very interesting, but the fact it is also a phenomenon used to protect us from counterfeit money makes it highly useful as well.

Boon