These inks are supposed to be invisible unless activated by light or heat, but in practice, you can usually still see a little bit of what’s written with the ink.

Create invisible ink with this UV pen making guide. Susan Collins' Re-Election Prospects Dim 10 Things You Should Never Clean with a Mr. Clean Magic Eraser Donald Trump's witness move fails in ...

In this challenge, I used a Smiggle Spy Pen to draw a full doodle using invisible ink that only appears under UV light! 🔦🖊️ Drawing without seeing the full lines in real time was tricky—but the ...

The agency releases six World War I-era documents, most of which deal with invisible ink.