What book am i thinking of?

[Would you rather?]

If anyone has read this book please tell me, i read it a long time ago and it was about a boy when he reached a certain age he was suddenly gained the ability to see color (which you learn later in the book that everyone sees black and white) and there was a guy that kept all memories, such as happiness, pain, colors, etc. and he would lay his hands on the kids back and transfer him memories daily

What book is this? anyone know?