A world without color would be a somewhat lifeless world. You wouldn’t be able to see the blueness of the sky, the color of your shirt, or even the color of your eyes. It would all just be black and white.
In Lois Lowry’s book, The Giver, no one could see color except for 2 people: Jonas and the Giver. Because of this absence of color, it added to the idea that everyone was the same and that the government wanted to keep it that way. They didn’t know the joys of a sunset, the fun of sitting around a red-orange campfire and roasting marshmallows, or even the colors of a flower.
So, if you couldn’t see color then you couldn’t even see the beauty of a rainbow– it would just be a thick grey-ish line in the sky. As you can see, a black and white world would lack many things.