# Passing counterfeit money

**URL:** <https://boards.straightdope.com/t/passing-counterfeit-money/1025471>\
**Category:** Factual Questions\
**Created:** [December 6, 2025, 7:48pm UTC](https://boards.straightdope.com/t/passing-counterfeit-money/1025471 "2025-12-06T19:48:44Z")\
**Posts on this page:** 2\
**Page:** 5

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [January 24, 2026, 1:52pm UTC](https://boards.straightdope.com/t/passing-counterfeit-money/1025471/81 "2026-01-24T13:52:41Z")

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Scanning IDs is something that people often have legitimate need to do.

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**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\
**Post date:** [January 24, 2026, 3:04pm UTC](https://boards.straightdope.com/t/passing-counterfeit-money/1025471/82 "2026-01-24T15:04:07Z")

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> [@scudsucker](#):
>
> I have heard (unsubstantiated) theories that the software detects specific patterns of tiny dots printed in yellow, which us humans can’t detect, that are added in the printing process.

Quite substantiated, although never explicitly confirmed by authorities.

> **[EURion constellation](https://en.wikipedia.org/wiki/EURion_constellation)**
>
> The EURion constellation (also known as Omron rings or doughnuts) is a pattern of symbols incorporated into a number of secure documents such as banknotes, cheques, and ownership title certificate designs worldwide since about 1996. It is added to help imaging software to detect the presence of such a document in a digital image, or scanners to detect such a document being scanned. The software or scanner can then block the user from reproducing such documents to prevent counterfeiting using c

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