Before the first shot
The look gets agreed in prep with the DoP and the colourist, usually as a show LUT and a handful of starting grades. On the day, the cart is built near set, cameras are checked against each other and every monitor is calibrated to the same reference.
During the day
Two jobs run in parallel. One is the image: live grading every setup so the director and producers see something close to the final look, and catching exposure, focus or flicker problems before they become reshoots. The other is the data: every card offloaded to at least two destinations, checksummed, logged and returned to camera.
If a card is lost, a scene is lost. The data side is the part nobody notices until it goes wrong.
After wrap
Grades are exported as CDLs, rushes are verified, and dailies get rendered, synced and uploaded so the edit and the studio can watch them the next morning.
Why this matters off set
The same pipeline works on a two-day brand shoot. You approve the look as it's filmed, your footage is backed up properly, and every film you commission matches the last one.