Method for showing hidden fingerprints through smoking of candles and candle smoke ash

A latent fingerprint and candle technology, applied in the field of fingerprint identification, can solve the problems of increased operational complexity, difficult to see clearly, iodine and 502 glue vapor toxicity, etc., and achieves a wide range of applicable objects, good application value, and satisfies the effect of simplicity.

Inactive Publication Date: 2014-05-21
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has high sensitivity, but the contrast between the white polymer fingerprint and the background on many light-colored and colored objects is weak, making it difficult to see clearly
Although some researchers combined the two ("502" gel plus iodine dyeing) to solve the problem o

Method used

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  • Method for showing hidden fingerprints through smoking of candles and candle smoke ash
  • Method for showing hidden fingerprints through smoking of candles and candle smoke ash
  • Method for showing hidden fingerprints through smoking of candles and candle smoke ash

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] A new method for displaying latent fingerprints on candle soot fumigation objects, taking a glass sheet with residual latent fingerprints as an example, the specific operation has the following steps:

[0036] 1) Take a candle and light it, the flame length is about 3cm;

[0037] 2) The detection surface of the glass sheet faces and is perpendicular to the flame, and cuts in horizontally from half of the flame;

[0038] 3) Move the detection material horizontally, 2 times / s, for 10s, or rotate the detection material 2 circles / s, for 5s, to collect soot;

[0039] 4) Remove the glass piece from the flame, cool it for a while, rinse it with tap water, you can get a clear fingerprint, and take a photo.

Embodiment 2

[0041] A new method for displaying latent fingerprints on candle soot smoked and plated objects. Taking the copper sheet with residual latent fingerprints as an example, the specific operation has the following steps:

[0042] 1) Take a candle and light it, the flame length is about 3cm;

[0043] 2) The detection surface of the copper sheet faces and is perpendicular to the flame, and cuts in horizontally from half of the flame;

[0044] 3) Move the detection material horizontally for 3 times / s for 15s, or rotate the detection material for 2 circles / s for 5s to collect soot;

[0045] 4) Remove the copper sheet from the flame and blow it with nitrogen to get a clear fingerprint and take a photo.

Embodiment 3

[0047] A new method for displaying latent fingerprints on candle soot smoked and plated objects. Taking wet paper business cards with residual latent fingerprints as an example, the specific operation has the following steps:

[0048] 1) Take a candle and light it, the flame length is about 3cm;

[0049] 2) Face the detection surface of the wet paper business card perpendicular to the flame, and cut horizontally from half of the flame;

[0050] 3) Rotate the test material horizontally for 2 turns / s for 2s, pause to let the test material out of the flame, then re-cut into the flame and rotate the test material for 2 turns / s horizontally for 2s;

[0051] 4) Take the business card out of the flame, rinse it quickly with tap water, you can get clear fingerprints, and take a photo.

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PUM

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Abstract

The invention relates to a method for showing hidden fingerprints on surfaces of various objects by adopting the candle smoke ash fumigation technology and belongs to the technical field of fingerprint identification. According to the method, burning candles serve as primary showing materials, the hidden fingerprints on the surfaces of the objects made of multiple materials (such as glass, ceramics, metal, paper and fingerprint adhesive tape) can be shown by the adoption of difference of the combination capacity between candle ashes and fingerprint valley areas and between the candle ashes and fingerprint ridge areas. The method specifically includes the first step of placing hidden fingerprint samples into burning candle flames and enabling the samples to be smoked and plated by the enriched smoke ashes, the second step of moving the samples out of the flames and applying external force to enable the candle ashes on the valley areas to fall off and keeping the candle ashes on the ridge areas, wherein the combination degree of the candle ashes on the valley areas is low and the combination degree of the candle ashes on the ridge areas is high, and the third step of shooting clear fingerprints through a digital camera. The method is simple, quick, friendly to environment and low in cost, and the method has the outstanding advantages that the hidden fingerprints on the surfaces of the objects different in permeability can be shown, and no complex instrument equipment or special reagent is needed. Thus, the method is ideal and can be used for showing the hidden fingerprints on site, and has good application value.

Description

technical field [0001] The invention belongs to the technical field of fingerprint identification, and relates to a method for revealing latent fingerprints by fuming candle soot. Background technique [0002] When the finger touches the object, the secretion covered by the skin texture on the finger surface will remain on the surface of the object correspondingly, forming a corresponding graphic impression. Some of these texture impressions are visible, and some are difficult to see directly with the naked eye. The latter are called latent fingerprints. These fingerprints are formed by the transfer of natural body secretions such as sweat and oil. Chemical and other methods make it appear or enhance and then collect information for application. The scientific discovery, extraction, and display of fingerprints have important practical effects on security, security inspection, criminal investigation, and punishment of crimes. [0003] In the history of more than 100 years o...

Claims

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Application Information

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IPC IPC(8): A61B5/117
Inventor 张美芹刘守亮朱雨王美玲于溪
Owner UNIV OF SCI & TECH BEIJING
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