Editing Counterfeit banknote detection pen (section)

==Reception==
Pen manufacturers claim such pens will detect a great majority of counterfeit bills and are an easy counterfeit detection method that does not require expensive gadgets.{{Citation needed|date=May 2013}}

===Critical reception===
Critics suggest the effectiveness is much lower.  Critics claim that professional counterfeiters use starch-free paper, making the pen unable to detect the majority of counterfeit money in circulation.<ref>{{cite journal
  |url= http://www.sciam.com/article.cfm?id=0001547E-EECE-1FD3-A7EA83414B7F012C
  |title= Bunkum!
  |date=January 2004
  |accessdate= 2008-03-28
  |first= Michael
  |last= Shermer
  |authorlink= Michael Shermer
  |journal= [[Scientific American]]
  |volume= 290
 |issue= 1
 |page= 36
 |doi= 10.1038/scientificamerican0104-36
 |bibcode= 2004SciAm.290a..36S
 |archiveurl= https://archive.today/20130202034612/http://www.sciam.com/article.cfm?id=0001547E-EECE-1FD3-A7EA83414B7F012C
  |archivedate= 2013-02-02
|url-access= subscription
  }} [http://www.ntskeptics.org/news/news2003-12-18.htm Alt URL]</ref>  Magician and skeptic [[James Randi]] has written about the ineffectiveness of counterfeit pens on numerous occasions<ref name="swift_2004-12-03">{{cite web
  |url= http://www.randi.org/jr/120304youve.html#1
  |title= Commentary
  |date= 2004-12-03
  |accessdate= 2008-03-28
  |first= James
  |last= Randi
  |authorlink= James Randi
  |work= Swift
  |publisher= [[James Randi Educational Foundation]]
}}</ref><ref>{{cite web
  |url= http://www.randi.org/jr/070105quality.html#7
  |title= Commentary
  |date= 2005-07-01
  |accessdate= 2008-03-28
  |first= James
  |last= Randi
  |authorlink= James Randi
  |work= Swift
  |publisher= [[James Randi Educational Foundation]]
}}</ref> and uses a pen as an example during his lectures.<ref>{{cite news
  |url= http://www.collegian.psu.edu/archive/2008/03/27/paranormal_skeptic_addresses_c.aspx
  |title= Paranormal skeptic addresses crowd
  |accessdate= 2008-03-28
  |last= Rowley
  |first= Erin
  |date= 2008-03-27
  |publisher= [[The Daily Collegian (Penn State)|The Daily Collegian]]
  |archive-date= 2008-03-29
  |archive-url= https://web.archive.org/web/20080329051459/http://www.collegian.psu.edu/archive/2008/03/27/paranormal_skeptic_addresses_c.aspx
  |url-status= dead
  }}</ref>  Randi claims to have contacted a [[United States Secret Service]] inspector and asked whether the pen works as advertised, to which the inspector replied "it is not dependable."<ref name="swift_2004-12-03"/>  The Secret Service does not include such pens in their guidelines for the public's detection of counterfeit US currency.<ref>{{cite web
 |url=http://www.ustreas.gov/usss/money_detect.shtml 
 |title=Know Your Money - Counterfeit Awareness 
 |accessdate=2007-11-06 
 |publisher=[[United States Secret Service]] 
 |archiveurl=https://web.archive.org/web/20071023030937/http://www.ustreas.gov/usss/money_detect.shtml 
 |archivedate=2007-10-23 
 |url-status=dead 
}}</ref>

US counterfeiters bleach small denominations and print more valuable bills on the resulting blank paper to evade this test,<ref>{{cite news
  |url= http://www.kspr.com/news/whereyoulive/greene/16592831.html
  |title= Businesses Lose out on Counterfeit Money
  |accessdate= 2008-03-28
  |last= Swallow
  |first= Natalie
  |date= 2008-03-12
  |publisher= KSPR
  |location= [[Springfield, Missouri]]
  |archive-url= https://web.archive.org/web/20080405085904/http://www.kspr.com/news/whereyoulive/greene/16592831.html
  |archive-date= 2008-04-05
  |url-status= dead
  }}</ref> although [[Federal Reserve Note#Post-2004 redesigned series|changes to the currency since 2004]] have made this method easier to detect.  This is one reason that many currencies use different sized notes for different denominations.

====False positives====

The effectiveness of the pens may be affected by external methods.  Simply having a banknote pass through laundry, depending on the soaps and bleaches used, can cause a bill to fail the test when it is otherwise accepted. Additionally, it was discovered that treating a counterfeit note with a dilute solution of [[vitamin C]] will cause a false negative: that is, it will respond to the iodine-based ink as though it were made of the same paper as a valid banknote.<ref>{{cite web|title=How do Counterfeit Pen Tests Work?|date=20 July 2017|work=Banknote World Resource Hub|author=Abdullah Beydoun |url=https://www.banknoteworld.com/resource-hub/portfolio/how-do-counterfeit-pen-tests-work/}}</ref>