Infrared luminescence
From Glossary of Forensic Document Examination & Pattern Recognition
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The infrared luminescence is a phenomenon encountered with some dyes used in inks and colored pencils that, when illuminated with a narrow band of light in the blue-green portion of the color spectrum, emit a luminescence that can be detected in the infrared or near-infrared range. The technique is useful in distinguishing between certain inks and colored pencils, and in detecting or deciphering erasures.
