Colour fluorescing inks are best used as a covert security feature.
They are similar to UV inks in that they will fluoresce under a UV lamp, yet to the naked eye they appear as a bright colour on the ticket.
This feature is excellent and very cost effective if your event involves night-time entrance or if you want a different hidden feature built into the ticket.
The sample below shows the ink (pink) fluorescing under UV light.