Northup was extremely good at using contrast. You see it constantly throughout the book. Most notably when he used it for nice slave owners vs. evil slave owners. Ford vs. Epps. For was a fairly decent man. He treated his slaves fairly nice, Epps on the other hand was pure evil. He beat his slaves ruthlessly.
Northup also used contrast when describing Patsey pre vs. post beating. This one really got to me. It really shows how horrible this beating was. She had been beaten before but this one was so horrible that it broke her spirit. Nobody should do that to another human.
One contrast that lasted throughout the entire book was the North vs. South. The contrast of this shows how he was treated like a normal human in the north and treated like animal in the south.
One contrast was Christmas vs. the rest of the year. There was a huge difference. The rest of the year they were treated very horribly. But Christmas time comes and they feast, they dance, they party. Like nothing ever happened.
These are just a few of the many things he uses contrast for. Contrast, in my opinion, is a very effective way of driving something home in the mind of the reader. In a book like this it brings home just how horribly they were treated. If you don’t show how different it is it wont make the reader think as hard and wont effect them as much.
For me I noticed more of the contrast in my life. See things like this vs. this. In my opinion contrast is very effective and should be used.