Surprisingly, for some reason, quite a few people know this effect on banknotes. Even competent cashiers who know about microtexts, microperforation, and metamer printing, for some reason they are surprised to learn about a simple but useful kipp-effect.
It is interesting that this protection is present even on the smallest banknotes - on dozens. Unfortunately, it is difficult to see it on worn-out banknotes, perhaps that is why this feature is rarely used. Do not know. However, the more signs you know and define, the less chances you will get a fake.
In one of the banks, where I was on a business trip, they gave me a five-thousandth bill. And they offered to determine exactly whether it was fake or not. In general, it so happened that I, never seriously interested in money and engineering safety, somehow imperceptibly began to understand it well, it so happened. And my eye became unexpectedly trained. The bill aroused suspicion instantly as soon as I saw it. It is clear that they wouldn’t have been offered her just like that, but there really was a very clear feeling: something was wrong with her. The color scheme and paper were weird. I turned it over in my hands this way and that, and individually, all the signs of authenticity seemed to be in place, even, it seemed, watermarks. And the steel strip was diving, although it aroused suspicion. And I used the check of two simple signs, one of which I want to tell you about. And not finding them on the spot, he declared with absolute certainty: a fake.
The colleagues nodded slightly in disappointment. Because at one time they themselves could not identify a fake with such confidence. If I understood correctly, even the bill acceptor ate it, it seems that this is how this bill got to them. But over the years I can lie.
By the way, nobody (then) carried this bill to the police. The bank simply wrote off 5,000 rubles at a loss. Because counterfeiting is such a serious crime that a small bank even prefers to incur a small loss, just not to get involved in the subsequent investigation. But the guys have a cool artifact.
So, this protection is called "kipp-effect". It is checked without any special tools. There is an ornamental stripe on the banknotes, if you look at it from a very acute angle to the light, you will see two capital letters "r" (which, as I understand it, means "Russian ruble", but this is not certain). It is important to find the correct position of the light source and the bill, without skill you will not see right away. I did not find a suitable picture, I have to use words.
It is necessary to stand in front of the light source, then place the bill almost on a straight line between the eyes and the light source. The bill should be almost parallel to this line (with a slight slope), just below it. Slightly changing the slope of the bill up and down, look at the ornamental strip. The light reflects off the bill very casually. At a certain angle of incidence of the light, notice the letters. It is convenient to take a bill with two hands, one in front, the other in the back, pulling it a little. Play around and find these icons. Depending on different circumstances, the letters will be light on dark, or vice versa.
This effect can be produced only with the help of a typographic technique called "metallography". Conventional offset printing in any of its variants will not create such an effect. (Actually, I am thinking of starting a "section" for a special printing house, where I will tell you a little about different technologies. If I feel ready for this, I will write. For now, very briefly.)
Metallography is a very expensive undertaking, it is justified only with very large circulations. Printing money is just that case. By the way, ordinary typography does not need all those special effects and precision that metallography gives. As a result, it is simply impossible to buy equipment for intaglio printing, the turnover is strictly controlled. In fact, there is a metal form in which cavities of different depths are engraved. Paint is applied, it is erased from the gaps, then the paper is pressed into this form under high pressure. It turns out, among other things, a certain relief. And as I understand it, it is with its help that the kipp-effect (microrelief of different heights) is achieved.
The main thing is to remember that one sign of authenticity is not enough! You need to know and apply at least 4-5.
