Method for extracting fingerprints:
The simplest thing in life is to use scotch tape, but it is also limited to extracting from fingers. If you want to see fingerprints in other places, then the simplest thing is to use milk powder, take a proper amount of milk powder, gently aim at the position with fingerprints, and then fingerprints will appear.
A program for processing fingerprints. Generally speaking, there are four steps to show an object: first, optical inspection, which finds, excites, extracts and fixes fingerprints through ordinary light sources, multi-band light sources, ultraviolet light sources and polarized light; The second is to use physical inspection, generally using Canon, BLACKPINK and so on. The third is to adopt physical and chemical methods, such as vacuum coating and VDM; The fourth is chemical methods, such as DFO, ninhydrin and 502. This greatly improves the success rate of fingerprint detection and extraction, and is conducive to the effective investigation of criminal offences.
Australian scientists have developed a chemical spray, which can help the police to extract the fingerprints left by suspects on rough surfaces. In the past, such fingerprints were difficult to obtain.
Catherine Flynn of the Australian Institute of Technology, her colleagues and the Australian police will publish their research and test results in the Journal of Forensic Medicine. This achievement was announced at a conference held in Sydney to commemorate the 0/00th anniversary of the introduction of fingerprint identification into Australia/KLOC-0.
Fingerprint is one of the most important means for police to identify and identify criminals, but in the past, it can only be extracted on a smooth surface. It is necessary to sprinkle fine powder such as aluminum powder and titanium dioxide powder on the fingerprint and adsorb it on the sticky fingerprint surface to make the fingerprint appear. This fine powder is cheap and easy to use, but when the powder attached to the fingerprint is brushed off, it will damage the 10% of the fingerprint and affect the recognition effect. In addition, once the fingerprint loses its stickiness, this method will fail. However, the biggest limitation is that this method is only suitable for smooth and non-porous impervious surfaces, such as bricks and rocks, and there is nothing to do with powder extraction.
In the past, scientists proposed to use a spray containing iodine pentafluoride or ruthenium tetroxide to extract fingerprints left on different surfaces. This spray is easy to use on rough surfaces and can be used quickly on a large area. However, no relevant results have been reported.
Catherine and her colleagues tested the fingerprint extraction effect of powder and spray, which provided the first comprehensive guide for Australian police on the best extraction effect of different fingerprint extraction media on various surfaces. They found that no fingerprint extraction method can be applied to all surfaces. For most surfaces, powder method is still effective, while chemical spraying can expand the scope of fingerprint extraction and create miracles on some special surfaces. On the surface of glass and treated wood, powder method is more suitable; Chemical sprays are more effective on wallpaper, vinyl and brick surfaces. Especially on some very rough surfaces, clear fingerprints can be obtained by chemical spraying, which is helpful for the police to solve the case. Because, even on the bricks and rocks in the outdoor crime scene, it is possible to leave fingerprints that are valuable for solving the case.
However, this chemical spray is harmful to human body, so we should pay attention to effective protection and clean up the scene in time after use.