Method for developing latent fingerprints through multi-metal deposition technology

A latent fingerprint and multi-metal technology, which is applied in the field of fingerprint identification, can solve the problems of complex and cumbersome operation steps, poor repeatability of display effect, and limitation of practical application, and achieve the effects of improving sensitivity, displaying quickly, and increasing application value

Inactive Publication Date: 2014-05-14
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the main disadvantage of this method is that the cost of visualization is high, the operation steps are complicated and cumbersome, and the repetition of the visualization effect is poor, which greatly limits its practical application in forensic identification.

Method used

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  • Method for developing latent fingerprints through multi-metal deposition technology
  • Method for developing latent fingerprints through multi-metal deposition technology
  • Method for developing latent fingerprints through multi-metal deposition technology

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Take the latent fingerprint of an object with a common double-sided adhesive as an example, the specific operation has the following steps:

[0037] 1) Using silver nitrate, ethanol and ultrapure water as raw materials, configure silver nitrate activation solution; weigh 20.00mg silver nitrate with an analytical balance, place it in a 10ml centrifuge tube, add 8.5ml ethanol and 1.5ml ultrapure water to the mark , Mix well and set aside.

[0038] 2) Prepare a copper plating solution with a copper ion concentration of about 0.15mol / L: weigh 2.028g copper sulfate pentahydrate, 6.1125g potassium sodium tartrate, and 2.4375g sodium hydroxide, and place them in a 50mL volumetric flask; glyoxal (40 %); When fingerprints are revealed, mix the two solutions in a volume ratio of 4:1.

[0039] 3) Add a few drops of silver nitrate activation solution to the surface of the latent fingerprint test material, react for 5 minutes at room temperature, and dry the remaining activation solution ...

Embodiment 2

[0043] Take the latent fingerprint of an object on a common transparent adhesive surface as an example, the specific operation has the following steps:

[0044] 1) Using silver nitrate, ethanol, and ultrapure water as raw materials, configure silver nitrate activation solution; weigh 31.00mg silver nitrate with an analytical balance, place it in a 10ml centrifuge tube, add 8.5ml ethanol and 1.5ml ultrapure water to the mark , Mix well and set aside.

[0045] 2) Prepare a copper plating solution with a copper ion concentration of about 0.15mol / L, weigh 2.028g copper sulfate pentahydrate, 6.1125g potassium sodium tartrate, and 2.4375g sodium hydroxide, and place them in a 50ml volumetric flask; glyoxal (40 %); When fingerprints are revealed, mix the two solutions in a volume ratio of 4:1.

[0046] 3) Add a few drops of silver nitrate activation solution to the surface of the latent fingerprint sample, and react for 15 minutes at room temperature. Dry the remaining activation solution...

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Abstract

The invention relates to a method for developing latent fingerprints through a multi-metal deposition technology, and belongs to the technical field of fingerprint identification. According to the method, silver particles and copper particles are successively deposited at fingerprint ridge line areas selectively so as to enable the fingerprint ridge line areas to be ash black while enabling valley line areas not to change, and therefore fingerprint morphology is developed. The method specially comprises the steps that a silver nitrate solution is used for activating the fingerprints, a fingerprint check material is immerged in a copper salt solution, and generated copper nano particles are adsorbed onto silver nano particles generated through activation. According to the method, latent fingerprints on various types of objects such as glass, stick band, ceramics and paper can be developed. Compared with an existing multi-metal deposition technology in which gold is used firstly and then silver is used, the method innovatively enables silver nano materials to be used before copper nano materials, so that the sensitivity and the resolution ratio of fingerprint development are greatly improved, meanwhile, the method is simple to operate, environmentally friendly, rapid, good in repeatability and low in cost, and greatly improves practical application value of the multi-metal deposition technology in latent fingerprint development.

Description

Technical field [0001] The invention relates to a method for displaying latent fingerprints by adopting multi-metal deposition technology, and belongs to the technical field of fingerprint identification. Background technique [0002] Fingerprints refer to the lines produced by the unevenness of the skin on the front of a human finger. The minutiae feature points of the fingerprint include the starting point, the end point, the joining point and the bifurcation point of the ridge and so on. Fingerprint recognition refers to identification by comparing the minutiae feature points of fingerprints. Because fingerprints have lifelong immutability, uniqueness and traceability, and because of their high extraction rate, reliable identification conclusions and direct identification of the person, they play an important role in the identification of physical evidence and the detection of cases. [0003] Fingerprint manifestation is to manifest (or enhance) latent or weak fingerprints int...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A61B5/117
Inventor 张美芹王美玲于溪魏千惠朱雨
Owner UNIV OF SCI & TECH BEIJING
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