In The Giver, how do they get rid of color?

We are never told exactly how they got rid of color, but it has something to do with science, as the Giver references this when talking about the color of flesh. 

In Ch. 12 Jonas is learning about color for the first time and this is when the Giver explains to him that things used to all have different shapes and colors. They talk about Fiona's red hair, the apple Jonas saw, and the color of faces. 

The Giver then chuckles and says,

"We've never completely mastered Sameness. I suppose the genetic scientists are still hard at work trying to work the kinks out. Hair like Fiona's must drive them crazy."

Then Jonas asks him about why they got rid of colors and this is the last we hear about the how - sort of. The Giver tells Jonas that the community got rid of color at the same time they got rid of sunshine, and then says, almost cryptically,

"We gained control of many things. But we had to let go of others."

So, we do not exactly know how colors were done away with, but we do know it has something to do with science, and that the scientists are still constantly perfecting Sameness.