This is a simple hitch, but for a long time I thought I was the only person that this didn’t work for. Using a grade node to match colors from a source plate ought to be a straightforward thing, but it isn’t. Set the black level on the new plate, set the lift on the source. Control click after picking the eyedropper in the black areas of each. Repeat for the whites, and that ought to do it.
But it doesn’t.
The hitch is that the grade node needs to be disabled when you do this. Otherwise the first color you pick will start grading and mess up the second color that you pick. It’s as simple as that. hit g to bring it in. Hit d to disable it, and then go about your business.
If that all wasn’t clear, then watch Frank Rueter do it on the link below, and remember to disable/enable it.