We know there are things that are intrinsically better done at the RAW development stage rather than with the TIFF at hand. Let's say if you want to apply curves or to correct white balance, you'd rather do that at an early stage, while developing the RAW image.
What about noise reduction? Is there an "intrinsic" advantage (for the algorithm, for the programmer, for the logic involved) in trying to reduce noise in the RAW file development phase rather than developing the RAW with all NR set to zero and than using a specialised program or Photoshop on the "developed" image?
On the one hand, programs such as Noise Ninja, Neat Image etc. are very "tweakable" and very specialized, and could have maybe better algorithm than those in, let's say, ACR.
On the other hand, maybe ACR has an "advantage" in separating noise from signal as it operates with the RAW image.
Experimenting did not lead me to any conclusion. Sometimes I feel it is better applying NR early, sometimes I feel it is better to apply NR with Photoshop. Maybe it all depends how "spot on" is the configuration of the NR in Photoshop for that image. Maybe a certain degree of NR is always better applied at RAW development stage.
Any comment appreciated
No image editing in raw format does any permament damage to your raw files, so experimenting with various workflow options is a free lunch to this extent. All noise reduction carries some cost in reduced acutance (undo-able in the raw file), so I generally don't reduce noise at the raw stage as I'm not keen to have a rendered image with reduced acutance. This is mainly because I often find that when I encounter noise, it is usually visble only in areas that can be easy to isolate on a separate layer and confine the noise reduction to those areas only. That way the acutance of the rest of the image remains unaffected by the noise reduction software. This cannot be done in raw - yet. Though in Camera Raw with CS3, you can sharpen the image and mask out the sharpening from frequencies where you don't want it to apply. All this considered, I generally use Noiseware for selective noise reduction on a separate layer if absolutely necessary, then Sharpen with PK Sharpener, both in Photoshop.