Question

Which development took place within the Northern International movement of the 15th century​

Answer 1

I believe it's the use of oil paints.

Answer 2

The oil painting and the impressive attention to detail.

Step-by-step explanation:

Jan van Eyck is by far the best-known artist of this period. He introduced the oil painting technique, which brought a new aesthetics for art. Its main feature is the chromatic mix and gloss giving exceptional finish, as well as flexibility due to the slow drying of the paint, allowing the artist to change his work when necessary.