How To Take A Fingerprint

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How To Take A Fingerprint
How To Take A Fingerprint

Video: How To Take A Fingerprint

Video: Forensics Expert Explains How to Lift Fingerprints | WIRED 2022, December
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Fingerprinting is clearly associated with only two things - police work and biometric sensors. Moreover, if a law-abiding citizen uses his own fingerprints, then someone else's biometric data may be required, most likely, by a lawbreaker. What is the process for making fingerprints?

How to take a fingerprint
How to take a fingerprint

Instructions

Step 1

The first step is to get a quality sample. This means that the fingerprint must be clear, complete, and not smeared. It is not possible to obtain such a sample from every surface. Smooth surfaces work best and will retain prints best.

Step 2

When the sample is received, it is necessary to develop the print. This can be done in several ways. The first method has been used for a very long time: graphite dust is applied to the sample, the excess is brushed off with a soft brush. That's it, the print is ready. You can fix the print with adhesive tape (adhesive tape).

Step 3

The second option involves the use of "Superglue". Pour the glue into a small container and hold the sample over it. After a while, glue vapors will settle on the lines of the pattern and give the necessary imprint.

Step 4

Next, the fingerprint is digitized. With the help of a high-quality camera, an image of the print is taken and transferred to a digital storage medium for subsequent work with it in a graphic editor. In a program for working with graphics, it is necessary to achieve a perfectly clear black and white drawing corresponding to the original size. The resulting drawing must be inverted.

Step 5

When the drawing is completely ready, it is transferred to a copper plate. The plate is etched, from which protrusions corresponding to the papillary pattern are formed on it.

Step 6

After that, silicone is poured onto the plate with the transferred image, which fills the grooves and protrusions. At this stage, the print is re-inverted - the depressions on the silicone surface turn into protrusions and vice versa. It was for this that it was necessary to invert the picture in a graphics editor.

Step 7

In the process of pouring silicone, air bubbles sometimes remain, which can ruin the whole picture. Using an ordinary syringe, you can create a kind of vacuum chamber: type silicone into the syringe and, closing the needle hole with your finger, pull the plunger up slightly.

Step 8

You can also apply a very thin layer of silicone to the copper first, wait until it dries, and then apply another. In conclusion, it remains only to dry the silicone and remove the finished print from the mold.

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