Did you have difficulty reading fingerprints in elections? understand the reasons

In the vote last Sunday (2), a 72-year-old retiree tried for almost ten minutes to confirm his identity through biometrics at a school in the city of São Paulo. He used the thumbs and forefingers previously registered with the electoral registry, but was unsuccessful. His fingerprints weren’t recognised. The solution was to inform the year of birth and, after voting, to sign the voting book.

These failures were frequently observed in electoral colleges and cited as one of the main reasons for long queues at many sessions, according to poll workers interviewed by the Sheet in Santa Cruz schools, in Alto de Pinheiros, in the west zone, Sion and Rio Branco, in Higienópolis, in the central region.

But why do these failures happen? In addition to technical reasons (reader quality, for example), there are several individual reasons, from poor hand positioning, too wet or dry fingers, to changes in the fingerprint pattern, caused by aging, cuts and abrasive substances.

People are born with a unique pattern of grooves on their fingertips, called fingerprints. It is based on this identification capability that fingerprint scanning technology was created.

“The region of the palm of the hand and soles of the feet, which we call glabrous skin, has an anatomy, an architecture, very characteristic. It is formed by protrusions and recesses, which form a specific design for each individual”, explains the dermatologist. Marcus Maia, professor at Santa Casa de São Paulo.

If the outermost layer of the skin (the thickest) is somehow flattened, these bumps and indentations can “erase”, which will make it difficult to read the fingerprints, adds the doctor.

One of the factors is aging. According to Marina Carrara, an orthopedist and hand surgeon at Hospital Sírio-Libanês, the skin becomes thinner and drier. “Hormones govern our entire physiology. And one of the effects of hormone reduction in old age is a decrease in the thickness of the skin layer.”

But it’s not just the elderly, says the doctor. For individual physiological reasons, there are people with thinner skin who may have problems reading fingerprints because they will, consequently, be very thin, which makes reading difficult.

Excessively dry fingers due to cold weather can also make the fingerprint difficult to read.
A tip in case this happens, according to Carrara, is to rub your fingers on your scalp to add body oils and a little moisture to the skin.

“With more fat, it ends up facilitating the contrast of the lines of the fingerprints. Sometimes, this little difference is enough for the system to read.”

Excessive sweat or cream on the hand can also make it difficult to identify the grooves, and the image obtained on the device does not match the one registered at the electoral registry. In these cases, drying your hands with a tissue sometimes works.

Maia, from Santa Casa, explains that during the Covid-19 pandemic, in which there was constant use of gel alcohol for hand hygiene, many people had difficulty reading fingerprints.

“I do digital checks at the hospital, I have to put my finger [no sensor]. There were days when it was crazy, it didn’t go away, I had to moisturize the skin a little to see if the bumps and indentations formed again”, says the 78-year-old doctor.

People who work in construction or cleaning, for example, are usually more exposed to chemical substances or physical processes and this can also change the architecture of the skin of the fingertip.

The good news is that, in general, the condition is not permanent: with the interruption of exposure to the agent causing the wear and the use of moisturizers, the small grooves in the skin of the fingers can re-form. That is, our body has the ability to restore them on its own, over time.

When there’s a big cut on my finger, for example, it forms a scar that can change a person’s fingerprint. In the same way that burns to the tips of the phalanges with fire or acid can totally wear out these birthmarks.

“If it messes with the architecture of the skin, when it has a scar, for example, the tissue that will form may not have the previous characteristics, that is, it will no longer look anything like the anatomy that the optical reader is used to, it will not will read. In these cases, you have to change your finger to read”, says Maia.