By analyzing them, they learned that cactus pulp was used as a binding agent.

Although, the use of oil as a binding agent can be traced to the 12th century, innovations in its handling and manipulation define the era.

To prevent this, one can add a stronger binding agent, like a thiol (in particular, alkanethiols), which will bind to gold, producing a near-permanent solution.

Also, plant pastes tend to smudge more easily than silk pastes due to the loose binding agent.

A binding agent such as gelatin or, more commonly, shellac may be added to make the ink more durable once dried.