A method for revealing latent fingerprints by fuming candle soot

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...

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 of iodine dye fixation and 502 gel fuming to visualize the light-colored background imaging, it also virtually increased the complexity of the operation.

In addition, the fumigated iodine and 502 glue vapors have certain toxicity, which is also a challenge to the health of on-site operators

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