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How to turn your phone into a Black Light: What you’ll need
The requirements for this particular project are very minimal. You’ll obviously need a smartphone with a flashlight capability (pretty much every one built in the last few years), some clear tape, plus blue and purple markers. You might also want some highlighter pens to create artwork that the blacklight can bring to life. We found yellow, pink, and orange worked the best.
How to turn your phone into a Black Light: Creating the Black Light
Take a small strip of clear sticky tape and place it over the flashlight LED on the back of your phone. Now gently colour the area directly above the LED blue.
Place another piece of tape over the first one, being careful not to smudge the ink.
Then repeat the first step but this time using the purple marker.
Now do the same thing again, alternating between the blue and purple colours. With those layers complete your Black Light is ready to test. Try drawing a simple pattern with your highlighter pens or writing a message on some plain white card. Then hold the phone above your work and turn on the flashlight.
‘What is this sorcery?’ we hear you cry, but fear not. Your phone now has UV-A light emitting from its flash and not much else. This means flourescent colours will leap out whenever you shine your light upon them, and you could probably take some very weird low-light photographs. Martyn has been involved with tech ever since the arrival of his ZX Spectrum back in the early 80s. He covers iOS, Android, Windows and macOS, writing tutorials, buying guides and reviews for Macworld and its sister site Tech Advisor.
