If you’ve ever wanted to know how much semen there is in a room that looks clean, there’s a simple trick to turn your smartphone into a black light.
All you need is Sellotape and two Sharpie pens.
This should work for just about any smartphone, provide it has a flash.
Black lights or UV lights are used by crime scene investigators to identify body fluids – including semen, sweat, saliva and urine. Semen happens to glow the brightest because of its particular mix of chemicals.
This is because bodily fluids fluoresce – that means they absorb ultraviolet light and re-emit it as visible light.
To create the semen-detecting tool, you need to take your phone and cover the flash with a small piece of sticky tape. Colour over the tape with the blue Sharpie pen.
Then add a second piece of tape over the top, colouring it in with the purple pen.
Then you need to turn on your flashlight app, et voila! You have a body fluid tracking tool.
Sorry about that.