HD proxie for 4K - protocol for connecting timeline to original 4K?

This is an IMAX film, shot in 4K. I'm coming in late here on the project, just trying to be helpful. They converted the 4K to HD (little bars on top and bottom), have done their edit in FCP 7.

They needed a quick colour grade for a screening in a smaller theatre.

I moved the project to FCPX, and did a colour grade (I was really impressed, I'd never used FCPX before).

Now I have a colour graded HD version of the film in FCPX. I'm wondering, just to demonstrate to the boys here certain possibilities, if I could relink the HD project to the 4K media – they would be able to run off a good working version, colour graded, of a 4K to try out in the bigger theatre?

And if such a thing is possible, what would the proper protocol be?

All ears,


Ben

Did you use any 3rd party plugins to do the colour grading in FCPX?