What Is the Chemical Composition of Pen Ink? By Sheila Johnson; Updated April 25, 2017 The twin tools of pen and ink have been in use since approximately 2500 BC, when Chinese and Egyptian societies independently developed writing ink. Today, pen ink is produced following a similar formula now as it was then: a color-rich substance is suspended with stabilizers in a liquid that a pen can push across paper. Innovations in chemistry since have added variety to ink's chemical composition.