Is this a Watermark?

Please can someone tell me if this is or isn't a watermark?
For something to be called a watermark - should it be visible from both sides of a note?
I ask this because the 2015 banknote 5 Ngultrum
has a small window/area on the Obverse - the digits here are only visible when tilted. It was not easy to obtain this photo.


This area is not visible on the reverse.
Thanks for your help.

Maybe more like a tactile security feature?

Thanks Idolenz.
At the start, I didn't realise this existed. It looked like a grey patch on the note.
Wonder if it reasonable to fill the add/modify data & load this photo?

Many security features are present on today's banknotes. IMO: the OP image appears to be "SPFX ink" according to the link.

Thanks Serial_Number_8.
I wonder how much of a detriment these security features have caused to the counterfeiters.

Quote: "BluHawk"​Thanks Serial_Number_8.
​I wonder how much of a detriment these security features have caused to the counterfeiters.

​Not as good as they'd like I'm sure (not '0' for instance). Law enforcement measures the # of fakes just like scientist calibrate contaminants (or pollutants): parts per million & paper fakes are still a big problem. The best measure against counterfeiting is still going polymer. The holographic windows are really tough to recreate cheaply.

Quote: "BluHawk"​Please can someone tell me if this is or isn't a watermark?
​For something to be called a watermark - should it be visible from both sides of a note?
​I ask this because the 2015 banknote 5 Ngultrum
​has a small window/area on the Obverse - the digits here are only visible when tilted. It was not easy to obtain this photo.
​
​
​This area is not visible on the reverse.
​Thanks for your help.

​If I remember right it is called a latent image.

RMA - Bhutan


edit: couldn't save the image in a larger size.

Quote: "BluHawk"​RMA - Bhutan
​
​
​edit: couldn't save the image in a larger size.

​very similar to what they do on some coins. 500 yen from Japan comes to mind.

Quote: "blue-m"​

Quote: "BluHawk"​RMA - Bhutan
​​
​​
​​edit: couldn't save the image in a larger size.

​​very similar to what they do on some coins. 500 yen from Japan comes to mind.

​Interesting, didn't know this technology was available for coins

To confirm: No, it's not a watermark. And like blue-m said, it is a latent image.

To answer your other question: Yes, watermark is cissible on both aides of the note when you hold it onto the light.

Watermark, both sides:


Latent image: