Development of latent fingermarks on thermal paper: Preliminary investigation into use of iodine fuming

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Development of latent fingermarks on thermal
paper Preliminary investigation into use of
iodine fuming
Om Prakash Jasuja Gagandeep Singh. Forensic
Science International, Volume 192, Issue 1,
Pages e11-e16, 20 November 2009
Persent by Pol.capt Nanthakarn Taljinda
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Introduction
Thermal paper

• Its extensive use in the modern day life
• Introduced by National Cash Register Company in
  1968
• Reaction Between leuco dyes and co-reactants

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Introduction
- Reaction involves opening ring structure
- Heat black
- Substituted fluoran different colors
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Introduction
Various techniques to develop

• - Ninhydrin
• 1,8-diazafluoren-9-one (DFO)
• dimethyllaminocinnamaldehyde (DMAC)
• - Metallo-porphyrin compound (TPP)Sn(OH)2

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Iodine fuming
Advantages
Simple method, is inexpensive, fast and
reversible Non-destructive paper or any writing
on the paper Developed fresh as well as age
latent fingermarks

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Iodine fuming
Disadvantages
The prints are not more than 1-3 day old Iodine
prints are not permanent and will fade, it
necessary to photograph the prints immediately
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Material and method

• Type of thermal papers
• Mitsubishi fax paper
• Oddy fax paper
• D.P. Print paper
• ATM paper receipts

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Material and method
Donors
10 donors their finger gentle rubbing of the
cheeks or forehead (sebaceous)
10 Donors their wash hands(eccrine)
Donors were placed on thermal papers
UV 5-10 min
Kept in dark
Iodine fuming
photograph
photograph
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Results and discussions
Permanency is dependent upon the type of thermal
papers
Mitsubishi and Oddy fax paper gt ATM paper and
D.P. print paper
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Results and discussions
Mitsubishi brand after 475 days
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Results and discussions
Different types of thermal paper resulted in
different colored fingermark
Mitsubishi , Oddy, ATM receipts green
/ greenish black
D.P. print paper
black / brown / yellowish
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Mechanism of the fingermark development
Iodine is electron-accepting
oxidize
leuco dye
open lactone ring
color formation
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Mechanism of the fingermark development
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Develop fingermark of iodine fuming
UVDark
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Formation of different color fingermarks upon
reaction with iodine
Green
Green color is produced by presence of two
tertiary amino group at 2 or 6 positions
2-n-butylamino-6-diethylaminofluoran
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Formation of different color fingermarks upon
reaction with iodine
Black
Black color is produced by methyl group at
3-position
2-anilino-6-diethylamino-3-methylfluoran
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Formation of different color fingermarks upon
reaction with iodine
Brown
Brown color is produced by replacement of amino
group at 2-position with azomethine group e.g.
6-diethylamino-2-ethyl-lidenaminofluoran
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Develop fingermark of iodine fuming
Develop fingermark of iodine fuming
a) Sebaceous b) Eccrine
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Develop fingermark of iodine fuming
i) Oddy brand ii) Mitsubishi
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Develop fingermark
Right by DFO
Left by iodine fuming
ATM paper
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Develop fingermark of iodine fuming
1 year old
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Conclusion

• - Developed fresh as well as age latent
  fingermarks
• No Background
• Permanent
• Clear and legible fingermarks
• Oxidation of leuco dyes
• Various color
• - It is sensitivity sebaceous marks

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