A method for revealing latent fingerprints by multi-metal deposition technology

A latent fingerprint and multi-metal technology, 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: 2015-09-23
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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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  • A method for revealing latent fingerprints by multi-metal deposition technology
  • A method for revealing latent fingerprints by multi-metal deposition technology
  • A method for revealing latent fingerprints by multi-metal deposition technology

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Taking the latent fingerprint of the object on the surface of the ordinary double-sided adhesive as an example, the specific operation has the following steps:

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

[0038] 2) Configure a copper plating solution with a copper ion concentration of about 0.15mol / L: weigh 2.028g of copper sulfate pentahydrate, 6.1125g of potassium sodium tartrate, and 2.4375g of sodium hydroxide, and place them in a 50mL volumetric flask; glyoxal (40 %); when fingerprints appear, mix the two solutions at 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 at room temperature for 5 minutes, ...

Embodiment 2

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

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

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

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

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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 a multi-metal deposition technology, and belongs to the technical field of fingerprint identification. Background technique [0002] Fingerprints are the uneven lines on the skin at the end of a person's fingers. The detailed feature points of the fingerprint include the starting point, ending point, joint point and bifurcation point of the ridge line, etc. Fingerprint identification refers to identification by comparing the detailed feature points of fingerprints. Due to the lifelong invariance, uniqueness and traceability of fingerprints, coupled with the high extraction rate of on-site discovery, reliable identification conclusions and direct identification of persons, fingerprints play an important role in physical evidence identification, investigation and case-solving. [0003] Fingerprint visualization is to display (or enhance) latent or weak fingerprints into cl...

Claims

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Application Information

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Patent Type & Authority Patents(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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