The Post-it Note Began as a Glue That Would Not Stick Properly

Somewhere near you right now there is probably a small yellow square of paper clinging to something: a screen, a fridge, the cover of a book, a door. It says milk, or call back, or a password nobody should have written down. It will stay put for as long as you need it and come off without a mark when you are done. That polite, temporary grip began as a disappointment.

In 1968, Spencer Silver was a scientist at the American company 3M, working on adhesives. He was trying to make a strong glue, the kind that might be useful for building aircraft. What he made instead was an odd acrylic adhesive formed of tiny spheres. It was tacky to the touch, it stuck easily, and it let go just as easily. It could hold two sheets of paper together and still let them be pulled apart without tearing, again and again.

It was a lovely material with no obvious job. Silver called it a solution without a problem, and for years he talked about it to anyone at 3M who would listen, in corridors and in seminars, hoping someone would think of a use. Nobody quite did, until a colleague called Art Fry, who had sat through one of those seminars, went to choir practice.

Fry sang in his church choir and marked the hymns with little scraps of paper, which had a habit of sliding out and fluttering to the floor as soon as the book was opened. In 1974 he remembered Silver's glue and wondered whether a bookmark could be made to hold on lightly without damaging the page. 3M let its staff spend some of their working time on projects of their own, and Fry used that time. The bookmark worked, and before long he and his colleagues saw that the real idea was a note you could stick anywhere and move again.

Even then it was a slow start. Tested in four cities in 1977 under the name Press 'n Peel, the pads sold poorly, because people did not understand them until they had used one. So in 1978 3M handed out free samples to offices in Boise, Idaho, and the response was overwhelmingly positive. The renamed Post-it Note went on sale across the United States on 6 April 1980. The famous canary yellow was an accident too: the team happened to have scrap yellow paper from the laboratory next door.

We know the story in such detail because 3M and the National Inventors Hall of Fame, which inducted both Silver and Fry, have documented it. The secret of the glue is the one Silver found in 1968: made of tiny spheres rather than a smooth film, it grabs quickly but holds only gently, so a note can be peeled off and stuck down again. The note also sold itself. People stuck them on documents they sent to others, and the people who received them wanted pads of their own.

It is a comforting story for anyone whose plans have not gone quite right. The glue failed at the job it was meant for and turned out to be brilliant at a job nobody had thought of yet. It just had to wait six years for a singer with a falling bookmark.