There is actually a really cool history of color grading and the advancement of computers in film technology. The movie O Brother Where Art Thou was the first movie to use full color correction, that was only possible with newer computer assisted editing, and lead to a Oscar award as well as future technical awards for its impact on film editing. Before that movie, color grading was seen as a last ditch effort to compensate for failings of a lighting director or poor cinematographer and was expensively and painstakingly done on select frames individually, and never done on more than a scene or two. After computers were used for digital editing and made it cheap, fast, and easy (relatively), it has become the standard. And now with digital cameras, it is literally baked into the process. It's a really fun rabbit hole to go down, would recommend.