[Help] Pure white background

[Xienix]

[This could be me posting it for the 2nd time cuz it didn't show up when i posted this when I hit submit]
Good afternoon everyone,

So I got some stock footage of a diamond, the idea is to get a pure white background without damaging the white background too much. I'm told that all I need to achieve the white background are levels and curves. I just can't figure out how, the ring is over exposed if I get the white background every single time....
here's what the footage looks like btw https://www.dropbox.com/s/l97bk48wdshu2cb/7.png?dl=0
if anyone is willing to help me out that would be amazing,

Thanks

[Duncan]

As a quick solution, you could draw a elliptical mask around the diamond ring, set it to subtract and feather it out a bit.

Then, under the Levels Compositing Options, add the mask. That way you're only affecting the masked area.

[Xienix]

As a quick solution, you could draw a elliptical mask around the diamond ring, set it to subtract and feather it out a bit.

Then, under the Levels Compositing Options, add the mask. That way you're only affecting the masked area.

Screen Shot 2016-06-27 at 3.59.54 PM.png

Thanks but the problem is that the small area around the ring is still grey, that's the problem I'd like to solve without damaging the ring too much or rotoscoping .-.