Sit in darkened rooms, spin 3 trackballs, and turn a few knobs to make pictures look pretty, mostly. DaVinci Resolve[1] and Baselight[2] are quite popular, take a look at the websites to give yourself an idea of what it looks like.

1. https://www.blackmagicdesign.com/products/davinciresolve/

2. https://www.filmlight.ltd.uk/products/baselight/overview_bl....

Hah, thanks! I should have been a little bit clearer - not an ELI5-layperson, a layperson who has some vague handwavey idea of how video/film is made and once read a popular article about orange/teal contrast.

It's more stuff like 'what is it about this process that makes a dedicated colour specialist necessary?', 'what are the things things they're supposed to accomplish?', 'what are their technical and creative constraints/inputs/deliverables?', etc.

Check out this YouTube tutorial to see the kinds of things they're doing with those knobs and panels.

The inputs are roughly "An ordered sequence of footage clips" and the output is roughly "A final projection/broadcast/download-ready movie"

https://youtu.be/ojjfhCrjDus