A UV torch does not light things up. It makes certain materials glow. Point one around your house and you will learn things you may not have wanted to know.
Why 365nm
Cheap UV torches run at 395nm and throw a lot of visible purple light. That purple washes out the glow you are trying to see. A 365nm light puts out far less visible light, so fluorescent marks stand out clearly.
What people use them for
- Banknotes and ID. Australian banknotes have features that glow under UV, including the serial numbers. Many licences and passports have UV marks too.
- Pet stains. Dried urine fluoresces. Check the carpet before the bond inspection.
- UV resin and glue. Cures UV-setting resin, fly-tying glue and screen repair adhesive.
- Leak detection. UV dye in air conditioning and engine systems shows where the leak is.
- Security marks. Read UV pen marks on tools and gear.
- Scorpions. They glow under UV. Useful to know before you put your boots on.
A warning
Do not shine a UV light into anyone's eyes, and do not stare at the LED.
The Nitecore Tube UV is a 365nm light that weighs 10 grams, lives on a key ring and charges by USB.