Want to turn a piece of my Art into a Black-light poster?

Unfortunately the best way to get something to become black-light reactive is to paint it by hand with reactive paints. Since it’s a poster though your best bet would be to call local printers and ask if they can print your artwork with black-light reactive ink.

You can have it silkscreened with reflective inks. “Monetizing” it is a whole other thing.

It would be an interesting market to explore, re-filling ink cartridges with florescent ink. Yellow, Cyan, and Magenta shouldn’t be too hard to do.

Silkscreening isn’t refilling carts , more like paint—
reflective element may be too coarse for in carts or react badly w/electrostatic process copiers use.
Might work in large-format ink jets [mural structure]

isnt there some sort of company that i can pay to create my poster?

If you want to try it yourself:
Glow in the Dark Silk Screen Ink!
Light-Green Glow in the Dark Screen Printing Ink. Light-Green. Light-Green. 2 Hours. SS-26. Light-Yellow Glow in the Dark Screen Printing Ink. Light-Yellow…
www.riskreactor.com/.../Glow_in_the_Dark_Silkscreen_Ink.htm