Development of latent fingermarks on thermal paper Preliminary

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 e 11 -e 16, 20 November 2009 Persent by Pol. capt Nanthakarn Taljinda

Introductio n 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

Introduction - Reaction involves opening ring structure -Heat black - Substituted fluoran different colors

Introduction Various techniques to develop - Ninhydrin -1, 8 -diazafluoren-9 -one (DFO) - dimethyllaminocinnamaldehyde (DMAC) - Metallo-porphyrin compound [(TPP)Sn(OH)2]

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

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

Material and method Type of thermal papers Mitsubishi fax paper Oddy fax paper D. P. Print paper ATM paper receipts

Material and method Donors 10 Donors their wash hands(eccrine) 10 donors their finger gentle rubbing of the cheeks or forehead (sebaceous) Donors were placed on thermal papers UV : 5 -10 min Kept in dark photograph

Results and discussions Permanency is dependent upon the type of thermal papers Mitsubishi and Oddy fax paper > ATM paper and D. P. print paper

Results and discussions Mitsubishi brand after 475 days

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

Mechanism of the fingermark development Iodine is electron-accepting oxidize leuco dye open lactone ring color formation

Mechanism of the fingermark development

Develop fingermark of iodine fuming UV: Dark

Formation of different color fingermarks upon reaction with iodine Green color is produced by presence of two tertiary amino group at 2’ or 6’ positions 2’-n-butylamino-6’-diethylaminofluoran

Formation of different color fingermarks upon reaction with iodine Black color is produced by methyl group at 3’-position 2’-anilino-6’-diethylamino-3’-methylfluoran

Formation of different color fingermarks upon reaction with iodine Brown color is produced by replacement of amino group at 2’-position with azomethine group e. g. 6’-diethylamino-2’-ethyllidenaminofluoran

Develop fingermark of iodine fuming a) Sebaceous : b) Eccrine

Develop fingermark of iodine fuming i) Oddy brand : ii) Mitsubishi

Develop fingermark Right: Left: by DFO by iodine fuming ATM paper

Develop fingermark of iodine fuming 1 year old

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