Hi Jim. Thanks for the link. I watched the video and tried Colorama but it’s not doing what I need. I’ve got another screen shot here just to clarify what it is I’m trying to remove from the shot:

If you look around the outer folds of the veil you’ll see some grubby-looking grey areas. Once color corrected they look fine as still frames but when viewed as video the changing values from frame to frame look really noisy.
I’ve toned it down quite a bit with the Remove Grain effect but it’s still just outside the boundaries of what’s useable.
(btw, I know the flowers have keyed out in this screen shot but I’ve worked around that in the actual comp 🙂 )