Stains add a whole layer of history to a document - I remember a prof at uni once apologizing for the wine stains on our papers...
In the same vein as stains, I love how non-waterproof inks react with water; the organic smudges and splotches add a bit of watercolor to an ordinary journal page (1).
In the same vein as stains, I love how non-waterproof inks react with water; the organic smudges and splotches add a bit of watercolor to an ordinary journal page (1).
1: https://nexus.armylane.com/files/Journal-Ink-splotches.jpg