P: Split noise removal for darks and highlights

maybe this is basically what people are saying here, but you could create a layer with your photo content, create a mask for luminosity, and then apply the filter.  Then combining layers would show the filter effect only in the desired luma range.  

Please notice that noise reduction option in CR filters has nothing to do with noise reduction section in Detail tab. It seems that this kind of noise reduction in allowed in filters is very simlified version of mentioned one. It makes this option almost unuseful. 

To people who want to achieve wonderful results in noise reduction: just use DxO Optics Pro 11 with prime noise reduction mode. I have never seen better quality of NR. Unfortunately there is no way to continue working with CR with RAW files. DxO can't save the results as RAW files :-(. 

Christian

1)Create a Gradient Filter with the 3 lines VERY close together.
2)Drag the center line so ALL 3 LINES are off the photo.  You may have to zoom out  to less than fit view to do this although I have always done it in fit view.  This essentially creates a mask over the whole photo you can adjust with the Range tool.
3)Apply the Luminance Range Mask to select either shadows or highlights
4)Apply local noise reduction.

I would probably use global noise for highlights and shadows and then apply further local noise using the above technique for extra noise in the shadows.

You can also use a large radial filter to select the whole photo but I find using the gradient filter much easier.

If you have any more question let me know.

PS. You can duplicate these masked gradient filters for more effect.

Robert Somrak, is there a tutorial anywhere regarding this way of noise-reduction? Since I am working as a stage-photographer, I have to deal with noise on relatively high levels (I am not using my Lumix G9 beyond 6400) regularly. using a masking filter like the graduated filter would really help

I think local adjustments and all other adjustments are parametric commands stored in a database.  Look at a preset with a simple radial filter.  It only has a few bytes of parametric data.  Photoshop layers can double the size of the file.

You can call them layers if you want.

Got news for ya... each local adjustment is basically a layer with a mask, but limited access to the controls. CaptureOne figured this out a long time ago, and miraculously the world didn't end after they implemented.

Probably don't need the options if your are using a mask.  

My hope is Lightroom never gets layers.  Leave layers to big brother Photoshop.  

for sure, but of course there are limited options for the local NR slider.

You don't need to add a layered/masked workflow to Lightroom to do this.  Just apply a Graduated Filter over the whole image and use the range mask luminance to select the shadows and apply the local Noise slider.  

if the LR team could implement a layered/masked workflow, then this problem would be a simple fix... use the range tool to create a mask for the shadows, apply NR.