UV ink

I put this on my context blog, but it effects my practice too so here's where I've got so far sourcing inks:

Ok, so I set this on my weekend action plan but I've only properly just sorted it out. The screen-print rooms have spot varnish stuff readily available, which is fine. They also have UV reactive ink, but it shows up in sunlight. They told me that as long as I find invisible ink that is black light detectable and water-based, it should eb fine to mix with the binder and work effectively.

http://www.blacklightworld.com/invisible%20ink.htm this website seems to stock this, but there's a few things I'm not sure about it, so I emailed them and I'm awaiting a response:

'Hi,
I was curious about your Black light, water based ink. How visible is it without a black light (I need it to be as invisible as possible)? Does it work under black light even when it's on darker surfaces? You say it's not permenant, but if I were to put it into a screen printing binder and use it on paper that wasn't to be exposed to water, would it last?

Thank you in advance.

Ben'

Hopefully this goes well, otherwise I need to start thinking of a contingency plan.

So these are the responses to my earlier posted inquiries about UV inks:
'Hi Ben
We do have such products but they are very expensive & only brought into order as follows:

UV-luminescent inks: They will glow only under exposure of black light (365 nm). So these inks are invisible under normal light and are colored under black light.

Or

Phosphorescent (glow in the dark, after glowing effect) inks: This kind of inks will be white under normal light and collect energy under day light. In the dark they will emit the energy and will glow in the dark.

Cost Per Kg approx. £250.00 plus shipping & VAT

Best Regards
Simon'- This was the response from a proper screen printing distributer, obviously thats ridiculously expensive and I figured that spot varnishing would become my only option. Then, however I found some water-based ink from blacklight world and their response was:
'I don't see a problem with your question. However the BLUE ink I would use only to show up bright on black paper. Keep in mind Im not a paper expert and different paper chemicals could cause different effect which is why I highly advise some experimentation with your paper or products to insure success.
Our Red & Yellow are for hand stamping and would not work well on paper especially black.


Thank You
Anthony' So, this is looking up because it's about £14 for 200g of UV ink, which should be more than enough, or at least I hope it will be. There's also some glow ink that Jonny wants so we're probably going to order together, as well as go halves on some paper stock when it comes to it. Which is great. The fact that the best one to use is blue is helpful because it can help define a colour scheme or code with the book it's self.