Scientific facts about paper money

We’ve got our mind on our money, and chemistry on our mind. That’s right folks, this week on Reactions we’re talking cash. Believe it or not, there’s stacks of chemistry rich facts about money. So, we compiled a list of our four favorite facts about the almighty dollar. The Federal Bureau of Printing and Engraving use washing machines for quality control. The Bureau produced about 26 million banknotes a day last year, which totals to around $1.3 billion. With all those bills being printed, you want to make darn sure that they’ll hold up in rough conditions, so the Bureau has some really high standards to keep.

The printers have to consider a huge amount of variables when testing money for durability. So, at the end of the production, Bureau scientists put their dollars through a beating with washing machines, cement mixtures, crumple tests, and a host of other challenges. Now, it may seem like a weird test, but the washing machine really isn’t all that out of place. After all, paper money is made up of the same stuff as your clothes, well cotton and linen to be more exact.

To ward off counterfeiters, money is printed with infrared ink amongst other specialized inks. The inks used to print cash are composed of organic pigments, inorganic pigments, varnishes, alkyds, and dryer agents like calcium carbonate, the same chemical used to make red fireworks. Go ahead and whip out that 20 again, and take a look at that shiny looking 20 on the bottom right of the front of the bill. A special optically variable ink is used to produce the color changing effect that allows the text to change from green to bronze. Infrared inks are used to hide secret features in bills, which makes counterfeiting really difficult. Infrared inks are undetectable by the naked eye, but do absorb light at higher wavelengths than we can see. These kinds of inks are extremely hard to come by, and to print with them requires serious precision, so there’s no use in trying to go print your own money you’re going to fail.

britannica.com