Complex sentence: Early on, he painted in the generally abstract expressionist style common among his teachers, but after his pause for reflection he began to draw and paint in a meticulous style of detailed representation which enabled him to give full expression to his inner world of images.
Split into simpler sentences: Early on, he painted in the generally abstract expressionist style common among his teachers. However, after his pause for reflection, he began to draw and paint in a meticulous style of detailed representation which enabled him to give full expression to his inner world of images.