• Title/Summary/Keyword: vacuum metal deposition (VMD)

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Comparison of vacuum metal deposition (VMD) and powder method for developing latent fingerprint on plastic envelope surface (플라스틱 봉투 표면에서 지문을 현출하기 위한 Vacuum Metal Deposition (VMD)과 분말법의 비교)

  • Kim, Chaewon;Lee, Narae;Kim, Taewon;Yu, Jeseol
    • Analytical Science and Technology
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    • v.33 no.3
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    • pp.159-166
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    • 2020
  • Vacuum metal deposition (VMD) is effective to develop latent fingerprints on non-porous and semi-porous surfaces. VMD can be used in cases when fingerprints that can not be developed by generalized techniques or deposited on difficult surfaces. The recommended surfaces for VMD techniques include vinyl, polymer bills, magnetic coated tickets, etc. In this study, the minimum amount of gold input was explored for developing fingerprints from at least 12 hours to up to 28 days after deposit fingerprint on the pink high density polyethylene envelope (HDPE) and low density polyethylene envelope (LDPE), which are mainly used as delivery envelopes. And the results were compared with the effects of black powder and fluorescent powder. In addition, delivery envelopes used for delivery were collected, then classified as HDPE and LDPE and pseudo-operation test was performed. As a result, VMD method developed good quality of fingerprints.

The effectiveness of vacuum metal deposition in developing latent grip impression on fabrics (Vacuum metal deposition의 직물에 잠재된 그립흔에 대한 현출 효과)

  • Seo, Bogil;Choi, Soohyeon;Jeon, Yugyeong;Yu, Je-Seol
    • Analytical Science and Technology
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    • v.33 no.6
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    • pp.240-244
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    • 2020
  • A grip impression is evidence of contact between the assailant and victim in a case. The shape of the grip impression can be analyzed to reconstruct which part of the palm it contacted. This study explored whether the grip impression left on cotton, nylon, and polyester fabrics can be identified by vacuum metal deposition (VMD). The latent grip impression developed by VMD had limitations in personal identification, but a new possibility was found that could be used as evidence for crime-scene reconstruction.

Comparison of VMD and 1,2-indanedione(SOON-100) for the Development of Latent Fingerprints on Thermal Paper (VMD와 1,2-indanedione(SOON-100)의 감열지 잠재지문 현출 효과 비교)

  • Jo, Hyunjin;Lee, Seon-Min;Yu, Je-Seol
    • The Journal of the Korea Contents Association
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    • v.20 no.11
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    • pp.333-341
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    • 2020
  • Since thermal paper is widely used in daily life such as convenience store receipts, lottery tickets and ATM receipts, it is important to develop fingerprints on thermal papers because it can be easily found in crime scenes. This study compared the ability of fingerprint development between vacuum metal deposition(VMD) and 1,2-indanedione(SOON-100) in order to evaluate the effectiveness of VMD, which some literatures have stated to be effective in thermal papers. As a result, in the case of SOON-100, clear ridges of fingerprints that enable individual identification were observed after an hour of deposition, although the fresh fingerprints were faint. In the case of VMD, the fingerprints gradually spread and the quality of the ridges deteriorated rapidly after 6 hours of deposition. This results is consistent with the principle of VMD. Considering the principles of VMD and the characteristics of the surface of thermal paper, VMD is not suitable for the development of potential fingerprints on the thermal paper.

A Study on How to Improve Empty Print to Cyanoacrylate Fuming Developed by Vacuum Metal Deposition (Vacuum Metal Deposition으로 현출된 Empty Print를 Cyanoacrylate Fuming로 개선하는 방법에 관한 연구)

  • Lee, Wonyoung;Kim, Youjin;Lee, Munhee;Yu, Jeseol
    • The Journal of the Korea Contents Association
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    • v.21 no.12
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    • pp.331-336
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    • 2021
  • Vacuum metal deposition(VMD) using gold and zinc is known as a very sensitive technique of developing latent fingerprints on nonporous surfaces by excellent malleability and ductility of gold. However, VMD produces empty print which cannot be identified. There is only presumption about the cause of occurrence of empty print, the exact cause is not known. In this study, we experiment on the freshness of fingerprints and sensitivity of techniques that are estimated as the factors causing empty print, based on this, we suggest cyanoacrylate fuming is effective to redevelop empty print.

Effect of silver (Ag) deposition before physical developer to develop latent fingerprints on wet paper (젖은 종이류에서 잠재지문을 현출하기 위한 physical developer 전 은 (Ag) 증착의 효과)

  • Wonyoung Lee;Min-Jeong Kang;Yoo-Jung Lee;Je-seol Yu
    • Analytical Science and Technology
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    • v.36 no.6
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    • pp.324-331
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    • 2023
  • Latent fingerprints on wet paper cannot be developed using amino acid reaction reagents. Therefore, physical developer (PD) or lipid staining reagents like oil red O (ORO) should be utilized. However, ORO is not very effective in developing fingerprints that are older than approximately 4 weeks. On the other hand, PD performs well in developing older fingerprints, but it cannot do so for relatively fresh fingerprints. Additionally, PD has the disadvantage of taking a long time to develop fingerprints. In this study, in order to overcome the limitations of PD, we attempted to increase its reactivity by applying Ag-PD, which involves depositing silver onto paper using vacuum metal deposition (VMD), and compared this with fingerprints developed using ORO and PD. As a result, Ag-PD showed superior fingerprint development compared to ORO and PD on wet paper stored for 2~8 weeks, and the fingerprint development time for PD was significantly reduced to 90~150 seconds.

A Study on STR Analysis According to the Method of Developing Latent Fngerprints Deposited on Non-Porous Surfaces in the Marine Environment (해양환경 내 비다공성 표면에 유류된 잠재지문 현출방법에 따른 STR 분석 연구)

  • Kim, Jin-Sun;Kim, Sea-In;Yoon, Hyun-Kyoung;Choo, Min-kyu
    • The Journal of the Korea Contents Association
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    • v.22 no.10
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    • pp.733-741
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    • 2022
  • Among the various evidence found in maritime crimes, fingerprints and DNA are very important in that they can identify a suspect. In this study, 5 types of non-porous surfaces (plastic, stainless, glass, ceramic, FRP), which are often found as evidence in the actual marine environment, were selected, and latent and blood fingerprints were passed down and immersed at the Donghae Maritime Police Station's exclusive pier for about 7 days. After that, DNA extraction, quantification, and STR profile were analyzed after fingerprint developing CA fumming method and 4 powder methods (Swedish black powder, Concentrated black powder, Supranano red powder, Dazzle orange powder). Among the fingerprint developing methods, when Supranano red powder was applied, a relatively high amount of DNA was found. As a result of STR profile analysis, an average of 16.8 to 9 loci were secured, and all 20 were confirmed in glass and ceramic materials. As a result of the study, it was possible to secure the STR profile by extracting and quantifying DNA after applying the fingerprint developing method to virtual evidence immersed for about 7 days, and further research is needed to secure the STR profile by analyzing DNA after applying various fingerprint developing methods such as VMD and SPR.