Part II: Casino Operations · Surveillance & Security
Card Marking Detection
Countermeasures
Surveillance techniques used to identify players or employees who have secretly altered playing cards to gain information about card values. Detection methods include monitoring for unusual hand positions, suspicious objects (invisible ink pens, special lenses), irregular play patterns, and visual inspection of cards under ultraviolet light. High-resolution surveillance cameras with specialized filters can sometimes detect subtle marks invisible to the naked eye.
In practice
Card marking remains one of the oldest and most persistent forms of casino cheating; modern methods use invisible inks detectable only with specialized contact lenses or glasses.
Related terms
More in Countermeasures
Advantage Play (AP)·Card Counting Detection·Counterfeit Chip Detection·Edge Sorting Detection·Game Protection Procedures·Security Seals·Shuffle Verification·Table Games Protection
One entry from the Casino Industry Glossary — 1,157 terms written for surveillance, compliance and operations professionals rather than for players. Definitions describe industry usage; where a term carries a regulatory meaning, verify against the instrument that governs your jurisdiction.