Infrared Fluorescent / Infrared Visible Ink
Our IR Inks and Pens are a new class of very high security inks. These inks are completely invisible to the human eye yet can be seen by using a device which can see in the infrared range - such as our modified cameras and camcorders. These inks do not fluoresce in the visible range, cannot be seen with ultraviolet lights and cannot be seen by the human eye alone.
The human eye can see from about 400nm (violet) to about 700nm (red). The human eye cannot see below 400nm or above 700nm. Below 400nm is the ultraviolet range and above 700nm is the infrared range. Please see our Vision FAQ for more information.
The nm stands for nanometer and is a measure of length. One nanometer is a billionth of a meter. The measurement is for one full light wave length.
IR1 Ink Properties
Our IR1 ink fluoresces at 840nm using and has a peak stimulation (absorption) frequency of 793nm. That means that if you want to see the writing of this pen, you can do so in three ways
1: Look at where the ink absorbs light
The easiest way is to look at where the ink absorbs light. Since the ink absorbs light a 793nm and emits light at 840nm, you want to filter out the 840nm light and look at the 793nm portion. By using one of our XNite 715nm filters on an IR sensitive camera or camcorder, you will be able to see the writing as dark marks.
We use a fairly concentrated form for the IR ink which can result in a very light green mark just barely visible to the human eye when the mark is on white paper. Using our 630nm filter, the human eye can see the IR ink fairly well unaided. Some customers have used these filters to make custom glasses to aid in viewing the ink.
2: Look at where the ink fluoresces
Another way to see this ink is by looking at the fluorescence of the ink. The ink will fluoresce in the same way as our UV inks fluoresce, but the IR1 ink fluoresces out of the human visible range.
You can stimulate the IR ink to fluoresce using visible or invisible light. The fluorescence of the ink will always be in the infrared rage.
3: Use our Infrared Ink Reader / Scanner
The IR Reader can see our IR Ink Pen writing as well as infrared marks on the back of currency. On the back of US currency, are invisible IR marks that are particular.
Here is a 100 dollar US bill. You can see the two white stripes with the reader
The reader has a color screen and long life internal rechargeable battery. You can save images to the device and later upload them to a computer via a USB cable.
This is an example image taken with the reader of a $50 bill
This is an example of the reader seeing our IR invisible ink.
The simplest method to see the ink is by using a 715nm filter such as our XNite715 with an infrared sensitive camera or camcorder.
Normal view. IR writing inside box is invisible.
Viewing IR Ink Absorption using a modified Fuji F30 camera and XNite715 filter.
Viewing IR Ink Fluorescence using a modified Fuji F30, XNite780 filter, 16LEDRed Flashlight with Concentration Lens.
Pen Model: IR1PenSm:
IR1 ink writing on white photocopy paper normal view.
These pictures were taken under normal light of standard white photocopy paper with writing from our IR1PenSm. The paper appears perfectly white.
IR1 ink on white photocopy paper viewed in infrared.
These pictures are under normal light using a XNite 715nm filter in conjunction with one of our IR enabled digital cameras.
The best way to see this writing from the IR1PenSm is using external IR sensitive equipment. On white paper, you may be able to perceive a very slight green mark from the pen. Using a 630nm filter, you can see the writing with the human eye.
You can use or IR1 ink to mark items invisibly to the human eye. We are the only manufacturer of this ink, and we do not know of anyone else selling such a product. Since you need special equipment to see the writing from the ink, it is highly unlikely that a casual or even curious person will discover how to see the ink much less find a way to duplicate it.
The IR1 ink does degrade under the ultraviolet rays of the sun in about 1 week. If the object marked is kept covered or away from the sun, the ink last a much longer time.
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