Amazing Inks – The Incredible Inks of Espionage

Happy Friday!  Today’s post – Amazing Inks – was shared from one of our readers.  You can read the original much cooler looking article here

~Source: Collins Inkjet – Amazing Inks


Throughout history, amazing inks have helped the clandestine communicate more effectively and with fewer risks. Used by governments, businesses and discreet individuals, these amazing inks have revolutionized the ways that secret messages are shared, high-value documents are authenticated and products are marketed.

LUMINOUS INKS -Inks that glow or fluoresce under UV light.


Forgery is a huge problem. In 2012, an estimated $220 million of counterfeit cash was circulating in the U.S. Luminous inks are used widely in the security field for preventing forgery of high value documents such as passports, banknotes and ID cards.


A cannon.At the end of the American Civil War, ⅓ of all American currency was counterfeit.
A mugshot.3,028 people were arrested for counterfeiting US currency in 2011.
A printer.In 1995, less than 1% of US counterfeits came from inkjet printers.

INVISIBLE INKS – Ink that becomes visible after being exposed to a stimulus.

1. Organic Fluids
Heat + Acid
Acid weakens the paper, causing it to darken or burn when heated

A candle heating a piece of paper. Lemon Juice + Heat

2. Sympathetic Inks – Agent + Reagent  – Ink is Invisible until reagent reacts chemically with agent

A top secret message. Baking Soda + Grape Juice

3. UV-Visible Inks  – UV Light + Fluorescent Ink  – Ultra Violet light triggers chemical reaction with ink A message written in fluorescent ink.


A bottle of ink.

Invisible ink was created in 1653 and was used extensively in spycraft during the Revolutionary War.  George Washington used a chemical form of agent and reagent to communicate with his spy ring. When writing to his supplier to request more, he would often refer to the reagent solution as his “medicine”.

A lemon and paper.

The US Central Intelligence Agency kept an invisible ink recipe written during World War I secret for over a hundred years, only declassifying it in 2011.  Eleven Germans were captured and executed by the British in 1915 after being discovered with lemons on their persons, or pens with pulp still stuck on the nibs.

Ink in water.

The Allies in World War II were the first to discover iodine vapor, a solution that turns all invisible inks brown.  Over the course of the war, the US government’s 14,462 censors opened a million pieces of mail a day; 4,600 pieces of mail were forwarded to the government’s labs, and 400 of these items turned out to contain secret writing and codes.


Inks whose color is altered due to a change in temperature.


Change color in response to variations in temperature

Change color in response to exposure to UV light

A handprint.

A ring.Mood rings of the 1970’s used the wearer’s body heat to signify his or her emotional state. In actuality, all they did was measure the wearer’s temperature.
A car.Giving your Hot Wheels™ a paint job was easy with Color Shifters. Run the car underneath hot or cold water to see a color transformation.
A mountain.Coors Light™ bottles and cans feature mountains that change from white to blue when temperatures drop to 45 degrees fahrenheit.
For more information on Amazing inks and what Collins Inkjet can offer, please click the link below.  Have first hand experience with any of these inks?  We’d love to hear about it in the comments section.
Have a great weekend!


4 thoughts on “Amazing Inks – The Incredible Inks of Espionage

    1. Very cool Greg – can you please send along the updated video to us through our contact us page? We would love to do a quick feature on the blog. Thank you for sharing and have a great weekend.

  1. Sorry Greg but that’s pretty common now.
    There are loads of apps with invisible embedded code and actually it’s all pretty copyable too.

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