Digital Infrared Photography and Banknotes

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kewl!!!

 

For years I was interested in infrared photography using film. When I got a digital camera I discovered that there is quite a difference in camera models when it come to IR ability. Usually the problem is many models place an IR cutoff filter in front of the sensor that makes them useless for IR photography but frees up those same wavelengths for other communications like triggering remote flash etc. I once had a Minolta d7i which had the filter but a slightly older model d7 that took great IR pictures. If interested in doing IR with your digital camera, check to see whether it works with those lengths.

If a camera is sensitive to IR, you need a filter to stop visible light. These filters range from very dark red to pitch black making it impossible to see what you are shooting. IR has always been good in determining fakes. In the old days it was well known that peroxide blond hair looked very different from natural blond when shot in IR. Real green leaves glow brightly in IR while green painted camouflaged tanks photograph dark. It is a good tool.

 

In my early days, I played with infrared film but used it to create artsy photos. I never spent much time to try to use professionally. Now I wish I had spent a little more time with it.

Here's some info on the camera I use:

http://irbuzz.blogspot.com/2007/05/ir-for-beginners-sony-nightshot-cameras.html

 

exactly the point i missed

To me, it never looked like it was part of the note. It seemed similar, but just seemed to odd with its pattern .... but i completely missed how it didnt fade as you mentioned lol

 

Interesting and thought provoking Thread



RB

 

I think the fiver from Wikipedia has this one pretty well covered, but just to add some information: The IR-vanishing stripe wasn't intended as a security feature, per se, but rather as a machine-readability feature. Handheld bill readers, such as those used by the blind, can just look for the IR patterns on the back of the bill to identify the denomination. The two green inks look identical under visible light, so the general public isn't even aware that the feature exists. By the way, this feature is pretty recent--the earliest printings of the big-head bills don't have it. It was added around the start of Series 1999, if I remember correctly. (Question for the guy with the camera: Do recent printings of $1's and $2's have any IR features on the backs? I'm not sure one way or the other....)

In a similar way, the intaglio portions of the *face* side of the bill are printed with two identical-looking *black* inks, having different magnetic properties. This allows for another form of machine-readability of the notes. The magnetic ink has been around for quite a while longer, all the way back to the later series of small-head notes.

 

Great info! Thanks numbers. :thumb:

 

I don't have any newer one's or two's at the moment. I'll see if we have any at work tomorrow.