My finger hovers over an iMessage obscured by a haze of dancing white dots. Before I tap to dissolve the sparkling pixels and reveal the contents of the message, I know it's going to be juicy, or at ...

The science experimenters at TKOR create hidden messages using invisible ink that only becomes visible under ultraviolet ...

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 ...