Invisible fluorescent paint -- bizarre instructions

[evilquoll]

I have ordered a bunch of invisible fluorescent paints in various colours from Neon Nights. (They use a similar kind of dye as are used in security marker pens; one which is transparent, and hence when it dries is virtually or completely (depending on surface) invisible under ordinary light, but under UV glows and becomes visible. The same kind of dye is also used to make beads which are white indoors under artificial light, but when exposed to sunlight (which is rich in UV) become brightly coloured.)

The firm have emailed me some instructions for use, and I find the last one baffling:

I have a few tips for you to make the paint glow best:

[...]

3) Use a UV-tube or black light energy saving bulb!

We explicitly advise not to use UV LED light technology, as the glow effect is incomparable to the "real" black light.

What are they on about? Surely UV is UV, regardless of source (indeed, I find that a blue LED is almost as good at making fluorescent dye glow, and at recharging luminous dye, as an UV one; I've heard that white LEDs are made by doping a blue LED with a fluorescent yellow dye to convert the UV to yellow, thereby producing a white light overall). The main difference is that for a given intensity, a LED source of black light uses only about half as much power as a fluorescent one (traditional tube or CF).

Are these people just being Luddite, or what? What does anyone else think?

[evilquoll]

I have now received the paints, and they glow just fine under both of the LED UV torches with which I tried them, so goodness knows what Neon Nights are on about...