How to extract fingerprints from articles?

It is impossible to extract correct fingerprints without professional tools.

Fingerprint method:

(1) observation method of blowing: observe blowing on the surface of a smooth object.

(2) Visual inspection: observe with certain light and angle. With the help of backlight, fingerprints can be displayed frequently. This is because fingerprints are often polluted by dust, which absorbs light and has a dark color.

(3) Magnifier observation method: With the help of a magnifying glass, observe the angle under a certain light.

(4) Ultraviolet observation method: observing with the help of ultraviolet characteristics.

(5) Theory and chemical observation method: The latent fingerprints that are difficult to be observed by naked eyes need to be chemically treated by auxiliary means.

(6) Cyanogel method: firstly, prepare Cyanogel solution and ether, soak the filter paper with proper size in the solution, take it out and dry it, and contact the filter paper with the fingerprint for 5-60 minutes. Under the action of glue, fingerprints near the paper volatilize and patterns appear on the surface of filter paper.

Extended data:

Precautions:

physical method

(Suitable for leaving fingerprints on the surface of non-absorbent objects such as metal, plastic, glass and ceramic tiles)

(1) powder method: select powder with high color contrast, sprinkle powder and extract complete fingerprints;

(2) Magnetic particle method, which uses fine iron powder particles and a magnet as brushes to display fingerprints back and forth.

(3) Laser method. With the development of laser technology, China uses laser to display fingerprints. The display device uses an argon ion laser. Laser can show fingerprints, because there is a layer of sweat and fatty acid on the surface of human fingers, which will leave inconspicuous fingerprints after touching objects.

Use laser, sweat, fatty acids, etc. Will produce color fluorescence, fingerprints are clearly visible. Use a special fingerprint camera to take clear fingerprint photos. The enlarged photos have brought great convenience to the appraisal work.

special

People with special diseases will leave "special fingerprints" at the scene, mainly because some diseases will change the patient's sweat. Just like diabetes, if you sweat a lot and leave fingerprints, you may see a group of ants and bees, as described in some novels or puzzles.

According to TV reports some time ago, some people drink tea with inferior porcelain cups for a long time, which leads to copper poisoning and red sweat. If a patient like this leaves a fingerprint, the result is red.

In Argentina, fingerprint evidence was used to make a woman confess to murdering her two children, which is the first time that modern fingerprint technology has been used in court.

With the development of science and technology, fingerprints have new applications in medicine. Some doctors have found that some diseases can be diagnosed by checking people's fingerprints and palm prints.

Fingerprints and computers have become good friends.

Many enterprises also use the characteristics of fingerprints to develop some high-tech equipment to reflect the convenience and security brought by fingerprints, such as fingerprint lock, fingerprint access control, fingerprint attendance machine, fingerprint scanner, fingerprint security, network fingerprint login technology and so on.

According to the survey, many high-end intelligent communities are equipped with fingerprint locks and fingerprint access control. The equipment used for fingerprint is the earliest fingerprint attendance machine, and the personnel manager of the company has been using the fingerprint attendance machine to prevent punching in.

At the same time, the first online fingerprint login technology provider in China has also launched a beta version, which is expected to solve the security problem of online accounts.

References:

Baidu encyclopedia-fingerprint detection

Baidu encyclopedia-fingerprint