"Colorizing" is a fun and unique way for beginner/intermediate photo editors to learn foundational pro tools in Photoshop.
Not only will you learn how to colorize a photo, but you'll learn the fundamentals of layers and selection tools - keystone tools for Photoshop dominance. Already a pro? You'll certainly still learn a few tricks in here.
Prior to the 1970's, color film was hard to come by. But now, with the magic of Photoshop (or similar programs), we can colorize old black and white photos to imagine historical images in more than just shades of grey.

More info
_https://www.skillshare.com/classes/photography/Colorize-History-Turn-Black-White-Photos-to-Color/1467473825