Luma Key (or Color Key or Ultra Key) not working on adjustment layers. Bug or limitation?

[Kata Lin]

Hi

I just noticed a big issue in Premiere Pro and I'm not sure if this is a bug or a nasty limitation (or maybe I'm doing something wrong). I tried to use an adjustment layer (over a couple of clips) that contains some effects and I wanted to use a Luma Key on this adjustment layer so the darker tones would become transparent, but it doesn't work. Here's an example: let's say I have this clip underneath the adjustment layer:

and on the adjustment layer I use a Mosaic effect and a Lumetri Color so I get this:

All good so far. Now I add a Luma key on this adjustment layer and I set the threshold to around 50% and I expect to get something like this:

                                   (this is made in Photoshop to ilustrate what I was expecting to get in Premiere)

But unfortunately what I get instead is this:

So the darker tones of the adjustment layer are not becoming transparent, they just get more darker.

Any thoughts?

[Kevin-Monahan]

Hi @Kata Lin,

Thanks for writing in. It may be workflow related. You may need to reroute the render order pipeline via nesting. Discard the use of adjustment layers for now. Duplicate the clip on V1 and V2. For the clip on V2, try keying the object then nesting it. Add the mosaic effect to the nest. Are you getting the results you were looking for now? Let the community know. I hope it works for you.

Thanks,

Kevin

[Kata Lin]

Thank you very much for the help @Kevin-Monahan!

Unfortunately, in my case, discarding the use of adjustment layers is not really an option as this would massively complicate my workflow. I need to use an adjustment layer because there are a lot of clips (and a lot of transitions between them) underneath it, so duplicating all those clips and aplying all the effects (and all the keyframing for the parameters of the effects) on every clip would be a huge PITA. Also, the mosaic+Lumetri effects was just a very simplified example, in reality I have a lot of effects (with a ton of keyframing) on that adjustment layer. So, as I said, getting rid of the adjustment layer is not really an option in my case.

[Ann Bens]

Your mosaic block are too large they need to be smaller to get the luma key working properly.