SJH UV fluorescent white ink test: a screen-printing air-dry ink that stays colourless and invisible under normal light, then glows bright white under 365nm UV. The formulation can be adjusted to suit different substrates and is also available for UV offset printing - covert security marking for cigarette packs, cosmetics, cards and labels.
A full written description of the demonstration, so the content is readable without playing the video.
This video demonstrates SJH UV fluorescent white ink: colourless and invisible under normal light, glowing bright white under a 365nm UV lamp. It is a screen-printing air-dry ink whose formulation can be adjusted to different substrates, with a UV offset version also available.
The video opens on the ink in its container - an opaque white paste. Note that the liquid appearance and the printed result are two different things: this is the unprinted ink, and only after drying into a film does it become colourless and invisible. You cannot judge a fluorescent ink by the colour of the paste; you judge it by how it prints on the substrate.
The camera moves to the printed sample. Under ordinary indoor lighting the two printed patches sit very close to the substrate tone, with no clear pattern edge. That is the point of covert fluorescent ink: the security feature stays completely hidden, takes up no design space and does not change the product appearance, so consumers never notice it in normal use.
As the UV lamp sweeps across the sample the printed areas light up in bright white fluorescence and the pattern edges become clearly visible, in strong contrast with the unprinted substrate. White fluorescence reads well on dark and full-colour surfaces, and it can be checked on site with a handheld UV lamp - no special instrument and no database lookup.
On-screen text notes that the ink is a screen-printing air-dry type whose formulation can be adjusted to suit different substrates, and that it is also available for UV offset printing. The same security feature can therefore be applied to paper, plastic and card stock without the printer redesigning the security scheme for each substrate.
| Appearance | Opaque white paste; colourless and transparent once dried |
|---|---|
| Under visible light | Print is invisible and does not alter packaging design or appearance |
| Under UV | Bright white fluorescence under a 365nm UV lamp |
| Printing | Screen printing, air-dry; formulation adjustable to substrate; UV offset version available |
| Verification | Handheld UV lamp on site - no instrument or database required |
| Typical use | Cigarette packs, cosmetics, cards and labels needing covert marking or a second-line check |
Fluorescent white differs from fluorescent yellow or blue in substrate compatibility: white fluorescence gives better contrast on dark and full-colour print, which suits packaging that is already printed in four colours and needs an extra covert check without a redesign. Where a higher security grade is required it can be combined with UV dual-band ink, so the same pack responds differently at different wavelengths. To decide fit, confirm three things: the substrate, the printing process (screen or offset) and the UV wavelength used at the inspection point.
Selection, detection, printing and ordering — answered.