What did "drinking ink" mean in ancient times?

In ancient times, this was an absurd legal provision.

During the Northern Qi Dynasty (550-577) in China's history, the imperial court ordered "those with poor grades" to be punished for drinking ink during the examination, and how much they drank depended on the degree of abuse.

Liang Wudi stipulates that: in the scholar's exam, anyone with poor books will be fined one liter; Even became a scholar, Lian Xiao, etc. Try again, when the invigilator finds that there is a "wave of arts and sciences, poor writing", ask him to drink a liter of ink in a special room.

This absurd rule has been followed for several dynasties, but it is not popular in the future, but remains in the vocabulary to describe learning by how much ink to drink.

Now it is often used to refer to going to school, which is a humorous usage. The collocation of different words can show people's cultural level. Such as: those who drink foreign ink, those who have never drunk any ink, those who drink too much ink, and those who have been drinking ink for several years.