The below description is taken from LEGO.com.
“Is this the right purple? It looks a little off…”
This Decorator does more than just paint houses. He’s also responsible for coloring each and every LEGO® brick! You didn’t think that they just popped out of a big machine that way, did you?
With the help of his handy roller, the Decorator adds shade and tint to elements as they come down the production line. He paints them on all sides, making sure to coat each stud on top and tube underneath, and he takes care to get any special details just right. So the next time you reach into a big box of bricks, remember who to thank for making them look so bright and colorful!