If you are a fan of CSI and other such cop TV series or movies, you will be familiar with a black light. It is an essential tool in a crime scene when looking for hidden blood, fingerprints or other bodily fluids. If the forensic scientist in you wants to solve a crime, or is just curious to see stains that are otherwise not visible to the naked eye, here’s how you can transform your smartphone to a CSI-like black light tool.
All you need for this trick is Sellotape and a pair or blue and purple markers. To create this forensic tool, cover the flash with a strip of Sellotape, and then color the flash with the blue marker. Repeat this process once. Again cover the flash with the Sellotape, but this time color the same spot with the purple marker. Voila, you have your homemade CSI-style black light.
All you need now is complete darkness and click a photo of a spot with your flash on. The resulting photo will show you the kind of stains covering the seemingly clean spot.
Check out the video below to see the DIY black light in action. Before you go all CSI on your home, a word of warning — what you end up finding in the dark might give you nightmares.