Ultra Violet Light Investigation

Aim of Experiment

Security pigments are used on important documents to help prevent fraud. These security pigments are invisible in normal light, but are revealed by ultra violet light. This experiment allows you to explore the range of security pigments on your important documents.

What You Need

• Ultra violet lamp
• Any (or all) of the following
  • Bank notes
  • Drivers license
  • Passport
  • Bank card/Credit card
  • Stamps
  • Prescription

An ultra violet lamp can bought in high street stores. We brought ours from Glowtec, but other on-line retailers also supply small cheap ultra violet lamps. Ultra violet lamps are sometimes called black lights.

What To Do

Shine your ultra violet lamp on the documents and see if you can find the hidden security markings.

The Science

Pigments can be made which react to certain types of light. Ultra violet light has a wavelength shorter than visible light. The security pigments absorb the energy of ultra violet light, and then emit some of the energy at a visible wavelength. This is why you can see the security pigments.