Carl Sandburg recorded in his autobiography, Always the Young Strangers, that his father carried an indelible pencil in his upper vest pocket when he dressed for church on Sunday morning. He may not have used the pencil, but it was there “just in case.”

The indelible pencil was put on the market in the 1870s. It was promoted as a tool for creating permanent copies of documents. The pencil was created by adding a water-soluble permanent dye to the powdered graphite and clay used in making it.

The aniline dye turned purple when moisture was added. As a child I can remember seeing people licking the pencil tip with their tongues to make writing appear as a deeper color on paper. Indelible pencils were frequently used for writing checks. Any tampering with the numbers could be seen easily. It should be noted that medical records of the nineteenth century show many injuries caused by the use of the indelible pencil.

To create a permanent copy of a document written with an indelible pencil, a piece of moist high quality tissue paper was laid over the document. It was pressed in a mechanical device. The tissue could then be held up to a light source and read in reverse. Businesses and governmental offices found this method very useful for keeping copies of important records. This method was used extensively during World War I for recordkeeping purposes.

Italy and other countries still require election judges to use indelible pencils on election materials to assure there is no tampering. During the nineteenth century, railroad conductors around the world were known for keeping their indelible pencils behind their ear.

By the 1930s the ballpoint pen was making inroads into the use of indelible pencils and the photocopy machine was on its way to being invented.