Education Technology

Forensics Case 5 - The Ink Is Still Wet: Using colorimetry to identify an unknown ink

Published on 06/17/2010

Activity Overview

In this activity, students identify the ink of a ransom note to match suspects. They identify an unknown ink by its light absorbance characteristics. The experiment set up used is to measure a solutions absorbance of different colors (wavelengths) of light.

Key Steps

  • Image

    Using the four settings on the colorimeter (Red, Green, Blue, Violet), solutions of different brands of ink pens are tested.

  • Image

    With the data compiled, each ink has a distinct profile making it possible to see if the ink sample from the suspect matches the specialized ink contained in the ransom note.