Verify, then approve

Two things get confused whenever somebody shops for a fix. Calibration sets a display to a target. Verification measures the display afterward and tells you whether it still matches that target. A probe is the small meter you put against the screen for either job.

A one-time calibration ages. Displays change as they warm up and as they get older, which is why the previous room put measurement on a schedule instead of on a date. What a probe gives you is verification, and knowing where a display stands today is worth more than a calibration you did once.

There is a limit worth knowing before any of this. Calibration can make a good display standards compliant. It cannot give a panel colors it was never able to show.

A second computer monitor does not change the answer either, because it is still the same desktop path. Resolve can fill one with a full-screen viewer through Video Clean Feed, which is in the Studio version only, and that is convenience rather than proof. The rung that changes the answer is a dedicated video output feeding a display you can measure. For professional work the advice is plain. Grade on a calibrated class A broadcast display, connected through a video interface. Class A means a display built and measured for reference work. Once you have one, its data levels setting has to match what that display expects. That setting decides whether black and white sit at the narrow video codes or the full ones. Get it wrong and the picture is wrong while the file is fine.

Until that rung, here is the sentence the last room was missing. Its stop, as this room's second section said, is a stop on approving. Grade, learn and build the structure. Then say exactly what you did: reviewed, not approved. How the finished file gets read back by a player somewhere else is a separate subject and a later room in this block.

The client hears none of that. They watch the work on whatever screen they own, and then they send you words. Turning those words into moves is the next room.