What if you used black cardstock and set the text color to be a really, really pale gray or blue? I too wanted to print white ink on vinyl sheets (to make window clings) and also discovered white isn’t possible. Really pale blue had pretty much the desired effect, though.
The inks in normal inkjet printers are transparent, so printing any color over black results in black.
I wanted to put white letters on my black painted instrument panel, got a label maker and white on clear tape. You can see the tape being shinier than the wrinkle paint panel, but it works Ok. Could stick the labels on cardstock to get what you want.
#whiteinkmatters
Oh well, I had a bunch of light blue stock I was going to turn into graph paper using white ink on the printer, but I guess I’ll have to think of something else.
In tattooing as well. A friend has a long, thin crescent shape tattooed on her arm. She had it done repeatedly in white ink, then allowed the area to tan. It looks kind of like a scar.
I used to have an Alps MicroDry printer that could print white. (I still remember the warning on the white ink cartridge, saying it would appear black when printed on a transparency and projected…) It’s a thermal transfer printer.
Also, this Oki laser printer can apparently print white.
Why don’t you just invert the colors? Is there some reason that that background must be black?
He’s trying to print custom cards for Cards Against Humanity. There are two sets of cards in a game, the beginnings of phrases, etc., which are white text on black, and fill-in words for those phrases and questions, which are black text on white.