Ink was once made from soot and glue, and it stayed dark for centuries.

The longer version

Soot is nearly pure carbon, which does not fade or react much with air, and it is made of particles fine enough to sit on a surface. Mixing it with a binder such as animal glue lets the powder stick to parchment or paper instead of rubbing off.

Carbon black is also indifferent to light, which is why pages written long ago can still read clearly while coloured dyes have faded. Iron-based inks behave differently: they bite into the surface and go brown with age, sometimes eating through the material if the recipe was poorly balanced.

Where this entry sits

This set looks at ancient civilizations, old inventions, trade routes, calendars, and the ordinary objects people once used every day. Nothing here is advice or opinion, just short notes about how daily life used to be organised long ago. The full list sits on the History page, where every entry is listed in order.