Alpha Matte Color Grading Workflow

Hi Everyone.
I'm relatively new to Davinci, so far it's great.
I'm having a VFX shot with an alpha matte. I managed to set the Alpha mate and do the key.
I have my background in one layer and my VFX shot in an upper layer.
The VFX shot matches with the background but both are LOG.
If I want to grade both at the same time, how can I do it? What's the popper way to color correct - color grade both?

Thanks in advance.
If it's not clear I can upload some screenshots.

Best!

As far as I know, you have to color-correct the background and the foreground separately. The only way to do both at the same time would be if you rendered that (either a compound clip or manually). It's not that hard to do them separately; I would stick with that.

It is possible to copy the grade for the foreground and apply it to the background (or vice-versa), so you can always use that as a starting point. The Unmix button is very helpful.

[Dmitry Kitsov BMD]

Hello, Victor,
In this case, where you have more than one layer and are using an alpha output there are at least few methods—here are 2:
there is an often overlooked feature in DaVinci Resolve, which allows you to group 2 or more clips and grade them together when necessary. If you are to select both plate and the VFX shot clips and chose to add them to a new group, you then will be able to switch the node tree mode from Clip to Group PreClip, and Group post Clip. Don’t forget to link them in the edit page, so they say together. You can read about the details on this workflows in the manual.
Alternatively you may select both of the foreground and a background clips in the editing timeline and make a compound clip out of them. In this case you can still grade them independently if you chose to open compound clip in its own timeline (kind of like peeking into the compound clip). This is less flexible because color adjustment effects are not retroactive (i.e individual clips comprising compound clip will not show the color applied to the compound clip when seen in the expanded timeline for individual adjustments), but might make it easier on a longer projects to make plate and the VFX clips to stay together in the context of an edit.

Ah, I forgot about Group Grades -- that's a great suggestion.

I'd still second Marc's suggestion (you can also copy and paste the nodes) mostly because you'll want to make small tweaks and adjustments to your VFX elements separately (at least in most cases).

[Dmitry Kitsov BMD]

@Kays—this is beautifully handled by the group grading workflow. As I mentioned, it is one of the most important, elegant and overlooked features that relates to the way one grades in Resolve, managing multiple clip grades while retaining great flexibility.
Copying grades can be done but is no longer necessary.

Wow, thanks for the answers.
They're really helpful. Specially for me as a beginner.
I'll check the Group Grades. And in case of any tweak, I'll do it separately.

Thanks!