The "Package Printing Really Is High-Tech" Story

It was an ordinary day.  Watching TV with my wife when I saw an advertisement on the screen that featured a bag of potato chips.  Asked my wife if she wanted any chips, since I was heading to the cabinet to get the bag of waffle-cut, sea salt chips.  She opted out of the chips, but asked me to bring the bag of pretzel splits to her.  Grabbed the bag of pretzels and one of the two bags of waffle-cut chips that I found and headed back to my seat with a glass of Pepsi.  Gave Carol the pretzels and put my drink and the bag of chips on my snack tray.  Then I saw it!  On the bottom edge of the chip bag was a printed line of nine small colored circles.  Instantly thought to myself...has to have something to do with the printing on the chip bag.  I taught Graphic Arts in high school for many years and we often talked about registration of colors while printing items such as books and magazines.  Should have realized that the small circles on the chip bag, as well as on the pretzel bag, were registration marks to keep the colors in the correct position so the printing looked more natural.  

Round registation marks on the back of the potato chip bag.

Then I grabbed the other chip bag and sure enough...there were the registration marks on it, but slightly different since the colored marks were rectangular instead of circular.  Began to read a bit about the printing of the bags and found that the colored circles come in a variety of colors in varying shapes.  Those colored shapes are called "printer's color blocks" or "process control patches" and are there to help the printers who print the packaging.  When the packaging is printed, technicians use the colored circles or squares to check that the printing ink is the correct color and quality.  They compare the color to boxes printed around the world to ensure consistent brand colors.  Most printers only use four colors: cyan (blue-green), yellow, magenta and black.  But, there are some printers that use extra colors such as orange and purple.  This is much the same as any printed item such as a magazine or book would do to make sure the colors line up and keep the same color from the beginning of the run to the end of the run.  And, evidently products that are made all over the world by the same company and wish to keep the same color on their packaging will also use the circles or squares to do the same.  Means that if you buy a pack of M&Ms in Shanghai, Sydney or Sacramento, the yellow packet of M&Ms will have the same thing inside of it.  Also read that the little squares on a tube of toothpaste help in the manufacturing of the toothpaste tubes by telling light sensors where the end of the tube is so that it can be cut and sealed properly.  

Toothpaste sleeves also have colored registration marks on them.

It really isn't a secret code, like I thought it was when I was a young boy, but something simple to help put the toothpaste in the tube or making sure that the packaging of chips or pretzel bags match from the west coast to the east coast of the United States.  Next time you buy a product, check out the packaging and see if you can find small colored circles, squares or even rectangles. If you do... you now know exactly why they are on the package.  It was another extraordinary day in the life of an ordinary guy.